The paving crew has left, the stripes are fresh, and the tenant wants to open next week. Then the final inspection stalls because nobody can prove where the storm line was laid or whether the parking lot drains the way the plans said it would. As built surveys solve that problem by recording what was actually built, measured in the field after construction. For commercial owners, developers, and contractors, ordering one at the right time can be the difference between a clean closeout and weeks of back-and-forth.

What As Built Surveys Document After Site Improvements

As built surveys capture the finished condition of the improvements covered by the project. On a commercial utility and pavement job, that usually means underground lines, structures, paved surfaces, curbs, and drainage features. The exact scope depends on the project, the engineer, and what the reviewing agency asks for. Some jobs need only the storm system, while others need every new feature on the site.

A typical commercial as built may include:

• Storm sewer pipes, inlets, manholes, and outlet structures
• Sanitary sewer lines, cleanouts, and manholes
• Water lines, valves, hydrants, and meter pits
• Pavement edges, spot grades, and curb lines
• Detention or retention areas and their outlet controls

Ask your engineer for the required list before the survey is ordered. Some owners also add items like light pole bases, sidewalks, and accessible parking areas. A clear scope keeps the surveyor from missing something the reviewer will ask for later.

Recording Installed Utility Locations and Elevations

Utility data is often the most important part of the survey, and it’s the hardest to collect once the ground is closed up. The surveyor records the horizontal position of each structure along with rim elevations and invert elevations. An invert is the elevation of the inside bottom of a pipe where it enters or leaves a structure. Those numbers show whether pipes have the slope needed to carry water or sewage.

Timing matters here. Some agencies or engineers want lines surveyed before backfill, especially for water services, bends, and connections that won’t have a visible structure. If the trench is already covered, the crew may have to rely on contractor notes or locate marks, which are less reliable. Talk with your surveyor and contractor early so the crew can catch open trenches at the right moment.

Pipe size and material should be confirmed as well. The surveyor can measure what’s visible inside a structure, but the contractor’s records help fill gaps. Matching both sources gives the owner a record that future crews can trust.

Verifying Pavement Grades, Curbs, and Drainage Features

Pavement grades control where rainwater goes. The surveyor takes spot elevations across the lot, along curb lines, and at high points and low points to confirm the surface slopes the way it was designed. Flat spots or reversed slopes can leave standing water that damages pavement and frustrates tenants. Catching these areas during the as built is far cheaper than fixing them after a hard winter.

Curbs and gutters get close attention too. The survey shows top of curb and flow line elevations, which reveal whether water will actually reach the inlets. Accessible parking spaces and ramps may also be checked, since slope limits apply to those areas. Local and project requirements vary, so confirm what your reviewer expects.

Detention basins, swales, and outlet structures round out the drainage picture. The surveyor measures basin bottoms, side slopes, top of bank, and outlet control elevations. Those numbers help the engineer confirm the basin holds the volume it was designed to store.

Comparing Completed Improvements With Approved Site Plans

The real value of the survey shows up when the field data is placed against the approved plans. Differences are common in commercial jobs because field conditions change. A water line may shift to avoid a buried obstruction, or an inlet may drop a few inches to fix a grading issue. Those changes aren’t always a problem, but they do need to be documented.

Many engineers mark the as built data directly on the plan sheets, showing design values next to measured values. That makes it easy for a municipal reviewer to see what changed and whether it still works. Large differences may require the engineer to run new calculations or ask the contractor to correct the work. Review the comparison as a team before submitting anything to the city or county.

Keep your tolerances in mind. Reviewers often allow small differences, but the accepted range can vary by agency, utility owner, and project type. Ask your engineer what tolerance applies so you know which items need attention.

Using As Built Survey Data for Project Closeout

Closeout often depends on as built records. Many municipalities and utility providers ask for as built drawings before they accept public lines, release bonds, or sign off on final occupancy. Lenders and owners may also want the records for their project files. Requirements differ by jurisdiction and project scope, so confirm them early in construction rather than at the end.

The final deliverable is usually a signed drawing plus digital files in the format the engineer or agency needs. Ask whether they want PDF sheets, CAD files, or data tied to a specific coordinate system. Store copies with the property records, since future expansions, repairs, and sales will all go smoother with accurate data on hand.

Frequently Asked Questions

What is an as built survey for commercial site work?

It’s a field survey that records the actual location and elevation of improvements after construction. On commercial sites, it often covers utilities, pavement, curbs, and drainage features. The data is compared to the approved plans to show any differences. Owners, engineers, and municipalities use it to confirm the work is complete and correct.

When should an as built survey be done?

Some parts should be surveyed during construction, before trenches are backfilled. Other parts, like pavement grades and curbs, are surveyed after final paving. The right timing depends on the project and the agency’s requirements. Schedule a conversation with your surveyor before utility work begins so nothing gets buried unmeasured.

Who usually orders the as built survey?

It may be ordered by the owner, the developer, the general contractor, or the civil engineer. The construction contract often states who is responsible. Check your contract early so the task isn’t overlooked. Missing this step near the end of a project can delay final approvals.