Key Takeaways
- Private utility locating finds the underground lines that 811 cannot mark — irrigation, landscape lighting, propane lines, septic systems, security wiring, and any utility past the meter.
- Public 811 service marks only utilities owned by member utilities up to the point of service; everything beyond is the property owner’s responsibility.
- Professional private utility locating services use Ground Penetrating Radar, electromagnetic equipment, vacuum excavation, and CCTV inspection to map non-conductive and unmarked lines.
- Construction projects, landscaping work, fence installations, and any digging on private property should always include a private locate before breaking ground.
- A 97% accuracy rate from a private locator using EM & GPR technology dramatically reduces the risk of utility strikes, project delays, and concealed safety risks.
Private utility locating fills the critical gap that the 811 Call Before You Dig system leaves on every property. While 811 marks public utilities up to the meter or service point at the property line, every utility line beyond that point is the property owner’s responsibility to identify before digging. Private utility locating services map those lines — irrigation laterals, landscape lighting circuits, propane gas lines, septic tanks, sprinkler systems, fiber optics, security and fire control systems, and any other privately owned underground line — so excavation can proceed without damage to the lines or risk to anyone on site.
We cover what private utility locating includes, how it compares to the public 811 service, the technology used to find non-conductive and unmarked lines, and the project types that require private locates before digging starts. Util-Locate has run private utility locating sweeps across California and Arizona since 2001, and the pattern on every site is the same: 811 alone never finds everything, and the lines it misses are usually the ones a homeowner or contractor doesn’t know exist.
Private Utility Locating Covers What 811 Cannot
The 811 Call Before You Dig service is a regional notification system that contacts the member utilities operating in your area — the gas company, electric company, water district, and similar facility owners. Once notified, those utility companies dispatch crews (often called 811 locators) to mark the public-owned lines that run to your property. Each 811 mark covers a single utility owned by a member utility, and coverage stops at the point of service.
What 811 does not cover:
- Privately owned underground lines past the meter or service point
- Lines installed by previous property owners that the utility company never recorded
- Landscape lighting and irrigation systems installed by contractors
- Lawn sprinkler systems, drip lines, and parking lot lighting circuits
- Septic systems, septic tanks, underground storage tanks, propane tanks, and propane gas lines
- Communications utility lines past the service entrance
- Security and fire control systems wiring
- Sub-meter electric lines feeding outbuildings, sheds, or pool equipment
- Any line that runs entirely on private property without crossing public right-of-way
Private utility locating exists for exactly these cases. A private utility locator company arrives on site with equipment that can detect both conductive and non-conductive lines, regardless of who owns them. The locator marks every line on the property — public and private — giving the property owner a complete utility map before excavation begins. For an overview of how this work integrates with the broader utility locating service, the service page walks through methods and deliverables in detail.
This complete picture matters because the consequences of a utility strike fall on whoever damages the line. If an 811 locate has marked the public utilities and a homeowner hits a private irrigation main, the homeowner pays for the repair. If a private sprinkler line crosses where a backhoe is operating, the contractor bears the cost — and the project delay — when it gets cut. Private utility locating is the only practical way to identify those lines in advance.
Private Utility Locating Services and the Lines They Detect
Private utility locators map a broad range of underground assets. The categories below cover the lines most commonly encountered on residential, commercial, and industrial properties across California and Arizona.
Sprinkler systems and irrigation systems. Drip lines, lateral feeds, valve boxes, and irrigation controllers all sit below ground on landscaped properties. A modern irrigation system can have dozens of branches under a single lawn. Hitting one disrupts watering, floods the area, and forces a repair before the original project can continue.
Landscape lighting and low-voltage circuits. Pathway lights, accent fixtures, and security lighting run on shallow low-voltage cable. The cable is often laid just inches below the surface and is easy to slice with a shovel during planting or fence work.
Septic systems. Septic tanks, leach fields, distribution boxes, and inspection ports all carry hidden risk. Disrupting a leach field contaminates soil and can render a system useless for months while repairs are made.
Propane tanks, buried tanks, and propane gas lines. Buried propane installations are common in rural and semi-rural California and Arizona properties. A strike on a propane line creates an immediate explosion or fire risk and qualifies as a major utility strike under state reporting frameworks.
Underground storage tanks. Heating oil tanks, water cisterns, and abandoned fuel tanks frequently sit on older properties without surface evidence. GPR scanning is the standard method for detecting them before construction starts.
Private water lines and well infrastructure. Service lines from a well house to outbuildings, secondary water feeds for guest houses, and any branch off the main water service after the meter are all private and unmarked by 811.
Communications utility and fiber optics. Private fiber installations connecting buildings on a campus, secondary phone drops, and any communication line past the service entrance fall outside 811 coverage.
Security and fire control systems. Wiring for perimeter sensors, gate operators, fire alarm panels, and integrated security systems often runs underground between buildings.
A reliable private utility locator company maps each of these line types, marks them with the appropriate utility marking colors, and produces a documented record that the property owner or project managers can use during planning and excavation work.
Public vs Private Locating: Comparing Coverage
The split between public and private locating is one of the most common sources of confusion for property owners and inexperienced contractors. The table below summarizes the practical differences.
| Aspect |
Public Locating (811) |
Private Utility Locating |
| Who performs it |
811 locators dispatched by member utilities |
Private utility locating service hired by the property owner or contractor |
| What’s marked |
Public utility lines up to the point of service |
All utility lines on the property, public and private |
| Cost |
Free |
Paid service |
| Lead time |
2–14 business days depending on state |
Same-day or scheduled, typically 24–72 hours |
| Lines covered |
Gas, electric, water, sewer, telecom to the meter |
Irrigation, landscape lighting, septic, propane, security, communications utility, and all other private lines |
| Accuracy rate |
Variable; coverage gaps common |
97% with modern EM & GPR technology |
| Documentation |
Paint and flags only |
Paint, flags, digital utility maps, CAD deliverables |
| Liability if missed |
Utility company bears partial liability |
Property owner / contractor bears full liability if line is unmarked private |
Once marked, every located line is flagged according to the standard utility marking colors used across both public and private locating — red for electric, yellow for gas, orange for telecom, blue for water, green for sewer, with additional colors for irrigation, landscape lighting, and other private utility lines.
The takeaway is straightforward: 811 is necessary but not sufficient. Every property has some combination of private lines, and any project that involves digging deeper than a few inches should pair an 811 ticket with a private locate. Skipping the private side is how strikes happen, and a 97% accuracy rate on the private locate is the difference between a clean excavation and a six-figure utility repair invoice.
Tools and Technology Used in Private Utility Locating
Modern private utility locating combines several technologies on a single site. Each tool handles a different category of line, and a complete sweep typically uses two or three methods in sequence.
Conductive and inductive electromagnetic locating equipment. Standard electromagnetic locators (EM) trace metallic lines and any non-metallic line equipped with a tracer wire. Direct connection produces the most accurate trace; inductive clamps and surface induction handle lines that don’t allow direct access. EM equipment finds metal pipe, electric line conduit, and any utility cable that accepts a radio frequency signal.
Ground Penetrating Radar (GPR) and GPR imaging technology. GPR scanning reads reflections off subsurface features and identifies non-conductive lines that EM cannot trace. Plastic water mains, PVC sewer lines, clay tile, fiber optics in conduit, and underground storage tanks all return distinctive GPR signatures. GPR also handles concrete scanning and concrete inspection on commercial slabs.
Vacuum excavation. Once surface methods identify a likely line position, vacuum excavation physically exposes the line to confirm depth, material, and exact position. This produces Quality Level A data under ASCE 38 standards — the most accurate form of subsurface findings.
CCTV inspection and high-definition inspections. Inside-the-pipe video confirms condition and routing of sewer line, process sewers, and storm drainage. CCTV is used alongside locating to verify that a marked line follows the expected path.
RTK GPS and GPS utility mapping. Survey-grade GPS captures the exact coordinates of every marked utility. The data feeds directly into digital utility maps and CAD deliverables that engineers, architects, and project managers can use during design.
Digital X-Ray imaging. For commercial concrete inspection, digital X-Ray imaging supplements GPR on critical structural elements where post-tension cables, conduits, and rebar must be precisely identified before drilling.
The combination of these tools produces a thorough picture of what’s beneath the property. A private utility locator using EM & GPR technology alongside vacuum excavation verification can typically locate every line on a typical site within a single visit.
Projects That Require Private Utility Locating Before Excavation
Almost any digging or excavation project on private property benefits from a private locate. The risk-versus-cost math tilts toward locating on almost every job. Below are the project types where private locating is effectively mandatory.
Construction projects. Any new build, addition, or major renovation that breaks ground should start with a private locate. The cost of locating is a fraction of the cost of a utility strike, a project delay, or a damaged utility cable that triggers an outage.
Landscaping and fence installation. Trenching for sprinkler lines, postholes for fences, tree planting, and hardscape work all penetrate the zone where private lines run. These projects produce the largest volume of avoidable strikes because they’re often done without any locate at all. Our guide to calling a private utility locator before backyard construction covers the homeowner side of this risk in detail.
Pool and spa installation. Pool excavation is deep enough to encounter every category of private utility — water, gas, electric, irrigation, and septic. A private locate before pool work is standard practice.
Solar installation. Ground-mount solar arrays, battery shed connections, and trenched conduit runs all need clear ground. Solar contractors who run a private locate first avoid the most common cause of project delays on residential installs.
Septic and sewer repair. Excavation around an existing septic system requires precise knowledge of leach field layout and tank position. Private locating combined with CCTV inspection produces both surface marking and inside-the-pipe confirmation.
Commercial site work. Parking lot expansions, parking lot lighting installations, signage foundations, and underground stormwater systems all require complete utility coverage before the first cut.
Property purchase due diligence. Some buyers commission a private locate before closing on a property with unknown infrastructure history. The locate produces digital utility maps that become permanent records for the new owner.
Any of these projects without a private locate is a gamble. The lines most likely to be hit are the ones the property owner doesn’t know about — the previous owner’s irrigation system, an old propane drop, a decommissioned underground storage tank, a security wiring loop. A private utility locating service finds these before they become a problem.
Standard Workflow for a Private Utility Locating Service Visit
A typical private utility locating engagement runs through a predictable sequence. Understanding the workflow helps property owners and contractors prepare for the site visit and get the most value from the service.
Initial site review and customer communication. The locator reviews the project scope, identifies what’s known about existing utilities, and confirms the scan area. Property owners share any records they have — old construction drawings, previous utility maps, contractor invoices that mention buried lines.
On-site walk and field locating. The crew arrives with a service truck loaded with EM equipment, GPR units, and any specialty tools the site requires. The walk covers the entire scan area, with marks placed for every utility identified.
Utility marking and color-coded flagging. Every located line is painted on the surface and flagged using member mapping conventions matched to standard color codes. Soil conditions, recent landscaping, and slope all affect how marks should be applied for durability through the project timeline.
Documentation and reporting. A professional service produces written documentation alongside the surface marks. Deliverables typically include a sketch, a CAD drawing, GPS coordinates for each utility, and notes on any limitations encountered. For complex projects, the report includes Quality Level designations under ASCE 38 standards used in utility mapping deliverables.
Post-locate consultation. The locator reviews findings with the property owner or contractor and explains anything unusual — corroded lines, conflicting records, or areas where additional verification (vacuum excavation, X-Ray imaging) would be wise before digging.
Util-Locate runs this workflow on every job, with documentation delivered in PDF, CAD, and KML formats. Our certified technicians work to ASCE-compliant standards and deliver the same precision on a backyard fence project as we do on a multi-acre commercial site.
Schedule a Private Utility Locating Service Before You Dig
Every project on private property has lines that 811 won’t find. The only way to dig safely is with a private utility locating service that maps the entire site before excavation begins. Util-Locate has been the trusted private locator for residential homeowners, contractors, and commercial property owners across Los Angeles, San Diego, Orange County, the San Francisco Bay Area, and Arizona since 2001.
Call 1-888-885-6228 to speak with a locating specialist, or request a quote for your next project. We respond 24/7 for both routine and emergency locates, and every job comes with the documentation you need to protect yourself from utility damage liability.
Frequently Asked Questions
What’s the difference between 811 and private utility locating?
811 Call Before You Dig is a free notification service that contacts the public utility companies serving your property. Those companies then dispatch 811 locators to mark only their own lines up to the meter or service point. Private utility locating is a paid service that maps everything beyond that point — irrigation, landscape lighting, propane, septic systems, security wiring, and any other privately owned underground line. Both are necessary for safe excavation; neither replaces the other.
Does my property really need private utility locating?
If your property has any of the following — sprinkler systems, landscape lighting, a propane tank, a septic system, security wiring between buildings, a pool with subsurface plumbing, or any utility line not directly serviced by a public utility company — then yes, you need a private locate before digging. The lines that cause the most damage during DIY projects are usually the ones the owner doesn’t realize are there. A 20-minute locate sweep almost always prevents a far longer and more expensive repair.
How accurate is private utility locating?
Modern private utility locating using combined EM and GPR technology reaches a 97% accuracy rate on the lines it identifies. The remaining 3% typically involves lines with broken tracer wire, deeply buried plastic mains, or conditions where soil composition limits signal penetration. Vacuum excavation verification can take accuracy to 100% on critical lines by physically exposing them for visual confirmation. The combination of surface methods plus targeted verification produces ASCE Quality Level A data on the lines that matter most.
Can a homeowner locate private utilities themselves?
Consumer-grade locators can find some metallic lines but miss most non-conductive utilities, including PVC water lines, fiber optics, and many irrigation systems. They also produce no documentation, no QC verification, and no liability protection if a missed line is later struck. For any project where the cost of a strike would exceed a few hundred dollars, hiring a professional private utility locator is the responsible choice.
How long does a private utility locating service take?
Most residential sites can be located in two to four hours, depending on size and complexity. Commercial sites typically require half a day to a full day. Complex projects with extensive subsurface infrastructure may need multiple visits paired with vacuum excavation and CCTV inspection. Documentation, including digital utility maps and CAD deliverables, is typically delivered within 24 to 48 hours of the field work.
