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<p><br></p><p>The calls we get come in two kinds. People scheduling a locate ahead of a dig, and people standing next to something they just hit, asking if we can come today. This post is about staying in the first group.</p><p>The short answer to "when do I need a private utility locator": any time you're putting steel, auger, trencher, or drill into developed private property. The rest of this is the longer answer, including the situations where you genuinely don't need us.</p><h2>The line 811 draws, and what falls on your side of it<br></h2><p>811 is mandatory and free, and it marks utilities owned by the utility companies, generally up to the meter or point of service. Everything past that point belongs to the property, and on commercial sites that's usually most of what's in the ground: parking lot lighting, irrigation, gas to detached buildings, private water and fire lines, data between buildings, old abandoned runs nobody remembers.</p><p>None of it gets marked on an 811 ticket. A <a data-mce-href="https://sitetwin.store/blog/locate-private-utility-lines" href="https://sitetwin.store/blog/locate-private-utility-lines">private utility locator </a>exists for that other side of the meter. If the property has been developed, built on, lit, or irrigated, the private side is not empty, whatever the drawings say.</p><h2>Hire one before these jobs, specifically</h2><figure id="figure-cyxxacphgmva4zm9l"><img id="cyxxacphgmva4zm9l" src="https://cdn.durable.co/blocks/38bOoPVkGQS0MbZTUCFfyJXffrJRiDyfKC5H11AYNkftXZfB8sgwIv7KL242acDb.jpg" alt="Roadway utility repair site in Texas" title="Roadway utility repair site in Texas" class="object-cover bg-gray-100 " style="aspect-ratio: 1/1; object-position: undefined undefined;" data-corners="default" data-aspect="1:1" data-caption="" data-positionX="undefined" data-positionY="undefined" data-fullWidth="false"/></figure><p>Some projects are locate-first jobs every time:</p><ul><li>Trenching or directional boring across any developed lot. Bores travel blind, and the crossings need to be known and the critical ones<a data-mce-href="https://sitetwin.store/blog/what-is-potholing-daylighting-utilities" href="https://sitetwin.store/blog/what-is-potholing-daylighting-utilities"> potholed </a>before the head is in the ground.</li><li>Fence, sign, bollard, and light pole installs. Shallow private lines and repeated holes along an alignment are a bad combination.</li><li>Foundation work, grade beams, and deep excavation near existing buildings, where old service runs cluster.</li><li>Saw cutting or coring slabs on grade, where the question is also what's embedded in and directly under the concrete.</li></ul><p>Any dig on a property you just acquired, because you inherited the previous owner's undocumented decisions.<br></p><h2>Hire one before you design, not just before you dig<br></h2><figure id="figure-uez1hsfxelmva4xwdw"><img id="uez1hsfxelmva4xwdw" src="https://cdn.durable.co/covers/3aIcolddGR9P9U0ERZHLfgRCoCEONIgZOmCOqQdtEyrjhPXlTGmw9ieVIHQqyBZK.jpg" alt="Water main break flooding a roadway after a utility strike" title="Water main break flooding a roadway after a utility strike" class="object-cover bg-gray-100 " style="aspect-ratio: 16/9; object-position: center center;" data-corners="default" data-aspect="16:9" data-caption="" data-positionx="undefined" data-positiony="undefined" data-fullwidth="false" data-mce-src="https://cdn.durable.co/covers/3aIcolddGR9P9U0ERZHLfgRCoCEONIgZOmCOqQdtEyrjhPXlTGmw9ieVIHQqyBZK.jpg" data-mce-style="aspect-ratio: 16/9; object-position: center center;"></figure><p>The least dramatic and highest-value locates happen in due diligence and pre-design. Finding out where the utilities actually run before layout is fixed means conflicts get solved on paper, where they're cheap. We've watched projects re-route a building's worth of conduit during construction because nobody investigated during design, and the cost difference between those two timelines is not small. If your project has a civil engineer, they will quietly love you for handing them <a data-mce-href="https://sitetwin.store/blog/as-built-utility-mapping" href="https://sitetwin.store/blog/as-built-utility-mapping">real utility mapping</a> instead of a forty-year-old as-built.</p><h2>When you can skip it<br></h2><p>Honesty clause. If you're digging on raw, never-developed land and 811 has marked the public lines crossing it, a private locate may genuinely have nothing to find, because there's no private infrastructure to investigate. Same for work that stays entirely inside the 811-marked public corridor. We'd rather tell you that than sell you a scan of empty dirt. The risk calculation changes the moment the land has ever held a building, a lit parking lot, or an irrigation system, and "the site looks empty" is not the same as "the site is empty."</p><h2>When in the schedule to call<br></h2><figure id="figure-ewsnwc6apfmva4ytta"><img id="ewsnwc6apfmva4ytta" src="https://cdn.durable.co/covers/343tZSxHW1QdOZcM7zl1HkSKp1dv7eDGeLaFoihDzl4xJJxXQJhcOIApnO9G0xTI.jpg" alt="Roadway utility repair site in Texas" title="Roadway utility repair site in Texas" class="object-cover bg-gray-100 " style="aspect-ratio: 16/9; object-position: center center;" data-corners="default" data-aspect="16:9" data-caption="" data-positionx="undefined" data-positiony="undefined" data-fullwidth="false" data-mce-src="https://cdn.durable.co/covers/343tZSxHW1QdOZcM7zl1HkSKp1dv7eDGeLaFoihDzl4xJJxXQJhcOIApnO9G0xTI.jpg" data-mce-style="aspect-ratio: 16/9; object-position: center center;"></figure><p>Ahead of mobilization, not the morning of. A few practical timing notes: your Texas 811 ticket requires two working days' notice and runs out in 14 days, so sequence the private locate in that same window and the whole site gets marked once, together. Define the work area before we arrive, round up whatever drawings exist, and arrange access to panels and mechanical rooms. A <a data-mce-href="https://sitetwin.store/blog/underground-utility-locating-methods" href="https://sitetwin.store/blog/underground-utility-locating-methods">locate</a> with scope, records, and access is faster, cheaper, and better than one without, every single time. Same-day and next-day mobilization is available in many Texas markets, <a data-mce-href="https://sitetwin.store/service-areas/dallas-utility-locating" href="https://sitetwin.store/service-areas/dallas-utility-locating">Dallas</a> and <a data-mce-href="https://sitetwin.store/service-areas/fort-worth-utility-locating" href="https://sitetwin.store/service-areas/fort-worth-utility-locating">Fort Worth</a> included, but the locates that go best are the ones that were on the schedule all along.</p><p>Got a dig coming up on developed property? <a data-mce-href="https://api.leadconnectorhq.com/widget/form/JeUXMeXP1NCxop51YesK?notrack=true" href="https://api.leadconnectorhq.com/widget/form/JeUXMeXP1NCxop51YesK?notrack=true">Schedule Utility Locate</a> - send the address and scope for review, and we'll tell you if it's a job that even needs us.</p><h2>Quick answers<br></h2><h3>What does a private utility locator do that 811 doesn't?<br></h3><p>811 notifies utility companies to mark their own lines, up to the meter. A private locator investigates the property side: the owner's lighting, irrigation, gas, water, and data lines that no utility company will mark.</p><h3>Do I need a private locate if 811 already marked the site?<br></h3><p>On developed property, usually yes. The 811 marks cover the public lines only. The private lines, often the majority on commercial sites, remain unmarked until someone investigates them.</p><h3>How fast can a private locate happen?<br></h3><p>Scope and location decide it, but same-day and next-day mobilization is available in many Texas markets. Scheduling it with your 811 ticket window is the clean way to do it.</p><p><a data-mce-href="https://sitetwin.store/services/private-utility-locating" href="https://sitetwin.store/services/private-utility-locating">SiteTwin | Private Utility Locating</a></p><p><br></p><p><br></p>

When to Hire a Private Utility Locator

<figure id="figure-kpnvikedemva3xzrg"><img id="kpnvikedemva3xzrg" src="https://cdn.durable.co/covers/3aIcolddGR9P9U0ERZHLfgRCoCEONIgZOmCOqQdtEyrjhPXlTGmw9ieVIHQqyBZK.jpg" alt="Utility crew working an emergency water main break repair in Texas" title="Utility crew working an emergency water main break repair in Texas" class="object-cover bg-gray-100 " style="aspect-ratio: 1/1; object-position: center center;" data-corners="default" data-aspect="1:1" data-caption="" data-positionx="undefined" data-positiony="undefined" data-fullwidth="false" data-mce-src="https://cdn.durable.co/covers/3aIcolddGR9P9U0ERZHLfgRCoCEONIgZOmCOqQdtEyrjhPXlTGmw9ieVIHQqyBZK.jpg" data-mce-style="aspect-ratio: 1/1; object-position: center center;"></figure><p>Every utility locating company's website says the same three things: experienced technicians, advanced equipment, safety first. True or not, none of it tells you who to put on your job. After years of being the second company called to sites where the first locate went wrong, we have opinions about what actually separates locating companies, and most of it never shows up on a website.</p><p>Here's what we'd ask if we were hiring one.</p><h2>Ask what happens when a line won't locate<br></h2><p>This is the question that sorts the field. Every company can trace a live electrical circuit with intact tracer wire. The job gets decided on the lines that fight back: poly gas with dead tracer wire, abandoned PVC duct, undocumented private water on a fifty-year-old site.</p><p>A good company has a real answer. They escalate methods, they work from surface evidence and records, they bring <a data-mce-href="https://sitetwin.store/blog/understanding-gpr-scanning--a-beginner-s-guide" href="https://sitetwin.store/blog/understanding-gpr-scanning--a-beginner-s-guide">GPR </a>when EM runs out, and when they still can't verify something, they tell you that instead of painting a guess. A company that never says "low confidence" isn't better at locating. They're better at hoping.</p><h2>One method is a red flag</h2><figure id="figure-dinv20bzglmva4030v"><img id="dinv20bzglmva4030v" src="https://cdn.durable.co/covers/36JiV0t5aKmHiPHHyohOMyabpWJOUwObxxy7ZV6kVLUjO0IQLwU5EIM1lVX63L09.jpg" alt="Utility crew working an emergency water main break repair in Texas" title="Utility crew working an emergency water main break repair in Texas" class="object-cover bg-gray-100 " style="aspect-ratio: 16/9; object-position: center center;" data-corners="default" data-aspect="16:9" data-caption="" data-positionx="null" data-positiony="null" data-fullwidth="false" data-mce-src="https://cdn.durable.co/covers/36JiV0t5aKmHiPHHyohOMyabpWJOUwObxxy7ZV6kVLUjO0IQLwU5EIM1lVX63L09.jpg" data-mce-style="aspect-ratio: 16/9; object-position: center center;"></figure><p>If the crew shows up with an EM wand and nothing else, they can only find conductive lines. Plastic pipe, empty conduit, and anything without tracer wire is invisible to them, and on a modern commercial site that's a meaningful share of what's in the ground. The honest minimum is <a data-mce-href="https://sitetwin.store/blog/gpr-and-em-utility-locating-services-explained--which-is-right-for-your-project-" href="https://sitetwin.store/blog/gpr-and-em-utility-locating-services-explained--which-is-right-for-your-project-">EM and GPR together</a>, used by someone who knows which tool to trust where. Ask what's on the truck. It's a fair question and the answer is revealing.</p><h2>Marks fade. Ask what you keep.<br></h2><figure id="figure-p4jedbq7qmva41q4m"><img id="p4jedbq7qmva41q4m" src="https://cdn.durable.co/covers/29b1eDtuptQrPEU3n5WpMtIw42rVsLvfV2Ruor8fkCx0Wt06dDdCLrc3h58eubSB.jpg" alt="Equipment mobilized for an emergency utility line repair" title="Equipment mobilized for an emergency utility line repair" class="object-cover bg-gray-100 " style="aspect-ratio: 16/9; object-position: center center;" data-corners="default" data-aspect="16:9" data-caption="" data-positionx="null" data-positiony="null" data-fullwidth="false" data-mce-src="https://cdn.durable.co/covers/29b1eDtuptQrPEU3n5WpMtIw42rVsLvfV2Ruor8fkCx0Wt06dDdCLrc3h58eubSB.jpg" data-mce-style="aspect-ratio: 16/9; object-position: center center;"></figure><p>Paint and flags are gone in weeks. If the deliverable is "we marked it," you own that information for exactly as long as the weather allows.</p><p>Ask whether you get documentation: mapped results, KMZ and PDF deliverables, photos of the marks, notes on what was found and what was low-confidence. On projects with design phases, <a data-mce-href="https://sitetwin.store/blog/as-built-utility-mapping" href="https://sitetwin.store/blog/as-built-utility-mapping">mapping deliverables</a> are the difference between a locate you use once and a record your whole project team works from. We include KMZ, PDF mapping, and reporting because the marks themselves are the least durable thing we produce.</p><h2>Can they verify, or only mark?<br></h2><p>Surface marks are estimates. When your bore crosses a gas line, somebody has to physically expose that pipe and measure it, which is <a data-mce-href="https://sitetwin.store/blog/what-is-potholing-daylighting-utilities" href="https://sitetwin.store/blog/what-is-potholing-daylighting-utilities">potholing</a>. Companies that only mark will leave you coordinating a second vendor for verification, which in practice means it often doesn't happen. Ask whether they identify which crossings need potholing and whether they can handle or coordinate it. The companies that treat verification as part of the job are the ones thinking about your excavation, not just their scan.</p><h2>Response time is a capability, not a perk<br></h2><p>Construction schedules don't wait politely. A locating company that books two weeks out will cost you more in idle crew time than the locate itself. Ask about mobilization honestly: we offer same-day and next-day in many Texas markets, from <a data-mce-href="https://sitetwin.store/service-areas/austin-utility-locating" href="https://sitetwin.store/service-areas/austin-utility-locating">Austin</a> to <a data-mce-href="https://sitetwin.store/service-areas/houston-utility-locating" href="https://sitetwin.store/service-areas/houston-utility-locating">Houston</a>, and when we can't make that window we say so up front, because a crew standing around waiting on marks is the most expensive kind of quiet.</p><h2>The boring paperwork matters<br></h2><p>Insurance certificates, the ability to get badged onto an active site, familiarity with your safety program, techs who can sit through an orientation without drama. None of this is exciting and all of it decides whether the locate happens on the day it's scheduled. A company that handles commercial and industrial work regularly will have this ready before you ask.</p><h2>What price actually tells you<br></h2><figure id="figure-9bpv71eelmva42n7z"><img id="9bpv71eelmva42n7z" src="https://cdn.durable.co/covers/38zHMlt5WjtSIpjpUYnKOilzGBynNkE03qFT3URhgDK9hYRbRBkSkgLTRUbsW0re.jpg" alt="Barricaded water line damage from an unverified excavation" title="Barricaded water line damage from an unverified excavation" class="object-cover bg-gray-100 " style="aspect-ratio: 1/1; object-position: center center;" data-corners="default" data-aspect="1:1" data-caption="" data-positionX="undefined" data-positionY="undefined" data-fullWidth="false"/></figure><p>Cheapest bid usually means fewest methods, fastest walk, no documentation, no verification. The locate is one of the smallest line items on your project and it protects some of the largest risks, so shaving a few hundred dollars here is bad math. That's not an argument for the most expensive company either. It's an argument for scoping: a defined work area, records provided, access arranged, and a quote based on the actual investigation. Vague scope produces padded bids from everyone.</p><p>Vetting locating companies for a Texas project? Ask us the hard questions, including what we can't do. <a data-mce-href="https://api.leadconnectorhq.com/widget/form/JeUXMeXP1NCxop51YesK?notrack=true" href="https://api.leadconnectorhq.com/widget/form/JeUXMeXP1NCxop51YesK?notrack=true">Schedule Utility Locate</a> or send the address and scope for review.</p><h2>The short version<br></h2><p>Hire the company that uses more than one method, tells you what it couldn't verify, hands you documentation that outlives the paint, handles or flags potholing, and shows up when your schedule needs them. <a data-mce-href="https://sitetwin.store/services/private-utility-locating" href="https://sitetwin.store/services/private-utility-locating">That's the job we built SiteTwin to do</a>, and it's the standard we'd hold anyone to, including us.</p><p><br></p>

How Contractors Choose Utility Locating Companies

<figure id="figure-esck857elsmv0brzhl"><img id="esck857elsmv0brzhl" src="https://cdn.durable.co/blocks/32drrGaQJkH5fFqNxTLFQ1wBoKF3p9YwHDsCMmxGtPZ8caGRic9jyz2Aopa3e8ne.png" alt="Diagram of a private sewer lateral running from a building cleanout to the public main, the part 811 doesn’t mark" title="Diagram of a private sewer lateral running from a building cleanout to the public main, the part 811 doesn’t mark" class="object-cover bg-gray-100 " style="aspect-ratio: 16/9; object-position: undefined undefined;" data-corners="default" data-aspect="16:9" data-caption="" data-positionx="undefined" data-positiony="undefined" data-fullwidth="false" data-mce-src="https://cdn.durable.co/blocks/32drrGaQJkH5fFqNxTLFQ1wBoKF3p9YwHDsCMmxGtPZ8caGRic9jyz2Aopa3e8ne.png" data-mce-style="aspect-ratio: 16/9; object-position: undefined undefined;"></figure><h2>How to Locate a Sewer Line on Your Property (and Why 811 Won't Mark It)</h2><p>Your sewer line is the one buried line nobody is coming out to mark. Texas 811 stops at the public main, and the pipe that runs from your building to that main belongs to you. It is also usually PVC or clay, which means a standard utility locator can't see it.</p><p>Here is how sewer lines actually get found, from the quick checks you can do yourself to the methods we use on commercial sites.</p><h2>Why 811 won't mark your sewer line<br></h2><p>When you call 811, the system notifies the utility operators with lines in your area, and each one marks what it owns. The sewer lateral, the pipe that carries wastewater from your building to the city main, is generally the property owner's line. Nobody is notified to mark it.</p><p>Where your ownership ends depends on the city. Some draw the line at the main, some at the property line or sidewalk, and some at a city-owned cleanout. Your city's water or wastewater department can tell you where yours changes hands.</p><p><strong>Still call 811.</strong> It covers the gas, electric, telecom and public water lines you may be digging near. It just won't cover this one. Our post on <a data-mce-href="https://sitetwin.store/blog/does-811-cover-private-property-in-texas" href="https://sitetwin.store/blog/does-811-cover-private-property-in-texas">whether 811 covers private property</a> in Texas explains the gap in more detail.</p><h2>Why sewer lines are hard to find<br></h2><figure id="figure-d2yxwzrkhwmv0btdvu"><img id="d2yxwzrkhwmv0btdvu" src="https://cdn.durable.co/blocks/34VsA84eGf3k4FCA0d6HeIH7vfXBK8Uw3XOFyIMKwgS8l4zZBk1eYQXkycMa16Qw.png" alt="Chart comparing EM locators, camera and sonde tracing, and GPR for finding PVC, clay and cast iron sewer pipe" title="Chart comparing EM locators, camera and sonde tracing, and GPR for finding PVC, clay and cast iron sewer pipe" class="object-cover bg-gray-100 " style="aspect-ratio: 16/9; object-position: center center;" data-corners="default" data-aspect="16:9" data-caption="" data-positionx="undefined" data-positiony="undefined" data-fullwidth="false" data-mce-src="https://cdn.durable.co/blocks/34VsA84eGf3k4FCA0d6HeIH7vfXBK8Uw3XOFyIMKwgS8l4zZBk1eYQXkycMa16Qw.png" data-mce-style="aspect-ratio: 16/9; object-position: center center;"></figure><ul><li><strong>They're usually not metal.</strong> Most laterals are PVC, ABS or clay tile, and older homes may have cast iron. Electromagnetic locators need a conductive pipe or a tracer wire, and sewer laterals almost never have tracer wire.</li><li><strong>They slope.</strong> Gravity does the work, so the line gets deeper as it runs toward the main. The depth at your foundation tells you very little about the depth at the street.</li><li><strong>They change over time. </strong>Repairs, reroutes and additions leave old pipe in the ground that doesn't show up on any drawing.</li></ul><p>For typical burial depths of the other lines on a property, see our <a data-mce-href="https://sitetwin.store/blog/water-line-depth-guide" href="https://sitetwin.store/blog/water-line-depth-guide">water line depth guide</a>.</p><h2>Start at the cleanout<br></h2><p>The cleanout is a capped 3- or 4-inch pipe that gives access to the sewer line. Look near the foundation, usually on the side of the building facing the street, and check flower beds and under mulch. Many newer homes also have a second cleanout near the property line.</p><p>Two cleanouts give you a rough line. A sewer manhole in the street can tell you roughly where the main runs. That's enough to plan around. <strong>It is not enough to dig beside.</strong> Laterals bend, and the only way to know the path is to trace it.</p><p>On a septic property, the line runs to the tank instead of a city main. Our guide on <a data-mce-href="https://sitetwin.store/blog/how-to-find-your-septic-tank" href="https://sitetwin.store/blog/how-to-find-your-septic-tank">how to find your septic tank</a> covers that case.</p><h2>Trace it with a camera and sonde<br></h2><figure id="figure-z7dtadd4samv0bu8e1"><img id="z7dtadd4samv0bu8e1" src="https://cdn.durable.co/blocks/30nQgM7wVfirbS42U80zXkGhwy9FW7VXTGQ4p7a5kUvccuHvCsJTnPL6BrhFrFiT.png" alt="Diagram of a sewer camera and sonde in the pipe, with a receiver reading depth and green paint marks above" title="Diagram of a sewer camera and sonde in the pipe, with a receiver reading depth and green paint marks above" class="object-cover bg-gray-100 " style="aspect-ratio: 16/9; object-position: center center;" data-corners="default" data-aspect="16:9" data-caption="" data-positionX="undefined" data-positionY="undefined" data-fullWidth="false"/></figure><p>This is the most reliable way to locate a sewer line. A push camera goes into the cleanout with a small transmitter, called a sonde, near the camera head. Above ground, a receiver picks up the sonde's signal, so the operator can walk the line, mark it every few feet and take a depth reading at each mark.</p><p>You get the location and the condition in one pass. The camera shows root intrusion, sags, cracks, offset joints and where other lines tie in.</p><p>The limits: you need an access point, a blockage or collapse stops the camera, and every depth reading is an estimate. If you need an exact depth before boring across the line, verify it with a <a data-mce-href="https://sitetwin.store/services/vacuum-excavation-potholing" href="https://sitetwin.store/services/vacuum-excavation-potholing">vacuum excavated pothole</a>.</p><p>When a camera can't make the run, a fiberglass tracer rod with a built-in conductor can be pushed through instead and traced the same way.</p><h2>Use GPR when there's no access<br></h2><p>No cleanout, no way in, or a line that was abandoned years ago? <a data-mce-href="https://sitetwin.store/services/gpr-scanning" href="https://sitetwin.store/services/gpr-scanning">Ground penetrating radar</a> doesn't need a conductor. It reads changes in the material underground, so it can pick up PVC and clay pipe that an electromagnetic locator misses.</p><p>GPR has a real limit in much of Texas: clay. Wet, heavy clay soils absorb the radar signal, and in the worst ground the useful scanning depth can drop to just a few feet. That's why we pair GPR with sonde tracing wherever we can get access, and why we tell you where coverage was limited instead of drawing a confident line through it.</p><h2>Sewer lines on commercial and redevelopment sites<br></h2><p>Commercial ground is where sewer locating gets complicated. A site that has been through several tenants can have:</p><ul><li>more than one active lateral, each serving a different part of the building</li><li>abandoned laterals from buildings that have since been demolished</li><li>grease trap and interceptor lines that don't match the original drawings</li><li>storm drains running close enough to be mistaken for sanitary sewer</li></ul><p>Before trenching, boring or excavating, every active lateral should be traced and possible abandoned ones flagged. That's the work our <a data-mce-href="https://sitetwin.store/services/private-utility-locating" href="https://sitetwin.store/services/private-utility-locating">private utility locating</a> crews do every day.</p><h2>What a sewer locate should give you<br></h2><ul><li><strong>Green paint marks</strong> on the ground. Green is the APWA color for sewer and drain lines.</li><li><strong>Depth readings</strong> at intervals along the run, not one number for the whole line.</li><li><strong>GPS points and a map</strong> (PDF and KMZ) so the locate is still usable after the paint fades.</li><li><strong>Notes on gaps:</strong> where the signal was lost or a section couldn't be verified.</li></ul><h3>Two things not to do<br></h3><ul><li><strong>Don't assume the line runs straight</strong> from the cleanout to the street.</li><li><strong>Don't trust one depth reading </strong>for the whole line. It gets deeper as it goes.<br></li></ul><h2>Frequently asked questions<br></h2><h3>Does 811 mark sewer lines?<br></h3><p>811 may notify the city about a public sewer main. The private lateral from your building to the main is not marked, because it belongs to the property owner.</p><h3>Can a metal detector find a sewer line?<br></h3><p>Only if the pipe is cast iron and shallow. PVC, ABS and clay pipe won't register on a metal detector or a standard utility locator.</p><h3>Can you locate a sewer line without a cleanout?<br></h3><p>Yes. A camera can sometimes go in through a pulled toilet or another access point, and GPR can scan for the line from the surface with no access at all.</p><h3>Who is responsible for the sewer line on my property?<br></h3><p>Generally the property owner, from the building out to the main or to the city's connection point. The exact handoff point varies by city, so check with your city's utility department.</p><h3>How deep is a sewer line buried?<br></h3><p>There's no single number. Sewer lines slope toward the main, so they are shallowest at the building and deepest near the street. Depth readings taken along the run are the only reliable answer.</p><h2>Need the sewer line found before you dig?<br></h2><p>Send us the address and what you're planning to dig, trench or bore. We'll trace the line, mark it and send you the map. <a data-mce-href="https://api.leadconnectorhq.com/widget/form/JeUXMeXP1NCxop51YesK?notrack=true" href="https://api.leadconnectorhq.com/widget/form/JeUXMeXP1NCxop51YesK?notrack=true">Send the address</a> and scope or call 512-968-5660.</p>

How to Locate a Sewer Line on Your Property | SiteTwin

Records vs. Reality: Why As-Built Drawings Are Not Enough to Prevent Utility Strikes

The Complete Guide to Private Utility Locating and SUE in DFW

<figure id="figure-4o6ykqyrh8mun6ermn"><img id="4o6ykqyrh8mun6ermn" src="https://cdn.durable.co/blocks/1aDy4cXuipMqUGyaI868nV1zsx0ro6jxUbEJH01hGa7fZab2Au9lMrmV5JgfL1Bb.png" alt="Concrete slab marked with a red grid and beam locations after a GPR scan" title="Concrete slab marked with a red grid and beam locations after a GPR scan" class="object-cover bg-gray-100 " style="aspect-ratio: 16/9; object-position: center center;" data-corners="default" data-aspect="16:9" data-caption="" data-positionx="undefined" data-positiony="undefined" data-fullwidth="false" data-mce-src="https://cdn.durable.co/blocks/1aDy4cXuipMqUGyaI868nV1zsx0ro6jxUbEJH01hGa7fZab2Au9lMrmV5JgfL1Bb.png" data-mce-style="aspect-ratio: 16/9; object-position: center center;"></figure><p>A post-tension slab is concrete that gets squeezed after it cures. Steel cables run through the slab inside plastic sheathing, and once the concrete is strong enough, a hydraulic jack pulls each cable tight and locks it against an anchor at the slab edge. The steel stays loaded permanently and holds the concrete in compression.</p><p>That matters because concrete is strong in compression and weak in tension. Rebar handles tension passively, only once the concrete has already begun to crack. Post-tensioning handles it actively, before there is a crack to resist at all.</p><h2>Why Texas builds this way<br></h2><p>Expansive clay. Soil that swells and shrinks with moisture wants to bend a slab, and a slab held in compression fights that far better than a passively reinforced one. Post-tensioning also lets you pour thinner, span farther, and cut down on control joints.</p><p>If you are in a Texas building put up in the last few decades, especially on clay, there is a real chance you are standing on one right now.</p><h2>How to tell if you have one<br></h2><ul><li>A stamped or cast warning at the slab edge or in the garage, usually some version of POST-TENSIONED SLAB, DO NOT CUT OR DRILL</li><li>Small patched pockets spaced along the perimeter, a few inches across, where the anchors were grouted over after stressing</li><li>Structural drawings calling for tendons, or a post-tensioning shop drawing in the project file</li></ul><p>If none of that is available and the building is the right age and region, treat it as post-tensioned until somebody proves otherwise.</p><h2>Where the cables sit<br></h2><figure id="figure-z2fojkd68rmun6fe9y"><img id="z2fojkd68rmun6fe9y" src="https://cdn.durable.co/blocks/33NC9bZ4UU1DRyx3NK87D07YhqecnNuRNiuwRiRD5FWQke5kCrYF4Zau0tnALfXp.png" alt="GPR scan markings laid out in red across an interior concrete slab before coring" title="GPR scan markings laid out in red across an interior concrete slab before coring" class="object-cover bg-gray-100 " style="aspect-ratio: 16/9; object-position: center center;" data-corners="default" data-aspect="16:9" data-caption="" data-positionx="undefined" data-positiony="undefined" data-fullwidth="false" data-mce-src="https://cdn.durable.co/blocks/33NC9bZ4UU1DRyx3NK87D07YhqecnNuRNiuwRiRD5FWQke5kCrYF4Zau0tnALfXp.png" data-mce-style="aspect-ratio: 16/9; object-position: center center;"></figure><p>Roughly mid-depth, and they do not run flat. Tendons are draped in a parabola, low through the middle of a span and higher over the supports, so the depth at any given spot depends on where you are standing relative to that span.</p><p>Spacing, depth, and layout are engineered per project. There is no rule of thumb safe enough to drill against, and shop drawings are a guide rather than an as-built record, because tendons shift during the pour.</p><h2>What happens if you cut one<br></h2><p>Each tendon carries somewhere in the range of 24,000 to 33,000 pounds.</p><p>Sever a loaded tendon and it releases all of that at once. The cable recoils, it blows concrete out of the slab, and it can seriously injure or kill whoever is holding the saw or the core rig. There are documented fatalities from exactly this.</p><p>The structural side is nearly as bad. You have removed a load path the slab was designed around, and the fix is an engineered repair rather than a patch. Depending on where the break falls, that can mean shoring, epoxy, external post-tensioning, or replacing a section.</p><h2>So can you ever drill or core one?<br></h2><figure id="figure-t7wdv3nnmun6g0gs"><img id="t7wdv3nnmun6g0gs" src="https://cdn.durable.co/blocks/12dsHLZXaDPdZOof85iK2mpJqeJNqokPiaQ1xQwcQgNk9vOLDoDpHw6OLM3F4oKB.jpg" alt="Red cones flagging painted scan marks on a concrete floor ahead of drilling" title="Red cones flagging painted scan marks on a concrete floor ahead of drilling" class="object-cover bg-gray-100 " style="aspect-ratio: 16/9; object-position: center center;" data-corners="default" data-aspect="16:9" data-caption="" data-positionx="undefined" data-positiony="undefined" data-fullwidth="false" data-mce-src="https://cdn.durable.co/blocks/12dsHLZXaDPdZOof85iK2mpJqeJNqokPiaQ1xQwcQgNk9vOLDoDpHw6OLM3F4oKB.jpg" data-mce-style="aspect-ratio: 16/9; object-position: center center;"></figure><p>Yes, routinely. It takes two steps, in this order.</p><p><strong>Locate the steel.</strong> Ground penetrating radar maps tendons, rebar, conduit, and slab thickness, and we mark the clear zones on the surface at the actual spot you want to work.</p><p><strong>Get the hole approved</strong>. Knowing where the steel is tells you where there is no steel. It does not tell you whether a hole in that location is structurally acceptable. That call belongs to the engineer of record, and on anything past a small anchor bolt you want it in writing.</p><p>Skipping either step is where this goes wrong. Scanning without engineering approval gets you a hole that misses the cables and still compromises the slab. Engineering approval without scanning gets you an acceptable location on paper and a severed tendon in the field, because the drawing and the slab disagree.</p><h2>When to scan</h2><figure id="figure-hndlch9q9mun6hmqu"><img id="hndlch9q9mun6hmqu" src="https://cdn.durable.co/blocks/25Twa8zD5qxv4xbSQRtxgwoRlwp24Y6xkrep2G73djsBgUtQV7oOVGAuCxLOmUNb.png" alt="Ground penetrating radar cart parked on a concrete walkway marked with white arrows" title="Ground penetrating radar cart parked on a concrete walkway marked with white arrows" class="object-cover bg-gray-100 " style="aspect-ratio: 16/9; object-position: center center;" data-corners="default" data-aspect="16:9" data-caption="" data-positionX="undefined" data-positionY="undefined" data-fullWidth="false"/></figure><ul><li>Coring for plumbing, floor drains, conduit, or dowels</li><li>Setting anchors for equipment, racking, handrail, or a car lift</li><li>Saw cutting for a trench, elevator pit, or slab opening</li><li>Demolition on or next to a post-tensioned deck</li><li>Any time the drawings are missing, unclear, or do not match what you see on site</li></ul><p>It is a couple of hours of scanning against a repair that runs into five figures and a real injury risk.</p><p>If you have a post-tension slab in Texas and need the tendons marked before you drill, <a data-mce-href="https://sitetwin.store/" href="https://sitetwin.store/">we scan it</a>.</p>

What Is a Post-Tension Slab? Why You Cannot Drill It

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SiteTwin provides professional utility locating, GPR scanning, and subsurface mapping services for construction, engineering, and surveying projects. We help contractors, engineers, and asset owners safely identify underground utilities, prevent utility strikes, and ensure project accuracy. Services include electromagnetic locating, ground-penetrating radar (GPR), GPS/GIS mapping, test holes, and detailed field documentation.

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Records vs. Reality: Why As-Built Drawings Are Not Enough...

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What Is a Post-Tension Slab? Why You Cannot Drill It