A failed sewer as-built costs more than documentation. When the city rejects your as-built package and requires field verification, re-excavation runs $180–240 per linear foot. Sitemark captures MH invert elevations, pipe run data, and depth of cover as you install — generating city-accepted as-built packages at job close, not weeks after.
City engineers and public works departments review sewer as-builts to verify that an installed gravity sewer system will perform as designed — specifically that it will convey flow at minimum self-cleaning velocity and that the infrastructure can be accurately located and maintained in perpetuity. The documentation standard is not optional; most municipalities tie final acceptance and release of surety to a conforming as-built submittal.
The core data every city engineer needs includes: manhole-to-manhole invert elevations (invert in and invert out at each structure), pipe size and material confirmed at each run, calculated pipe slope between each MH pair, depth of cover at road crossings and at each structure, and GPS or surveyed coordinates of every manhole. Rim elevations at each manhole are required in virtually all jurisdictions.
Many municipalities follow or adapt the ASCE Manual of Practice No. 36 (Design of Sanitary Sewers) as the basis for their as-built requirements. MOP 36 sets minimum velocities, maximum slopes, and pipe sizing guidelines. When a city asks why a slope of 0.4% fails their minimum, the answer traces back to the self-cleaning velocity requirement: at less than 2 fps, solids settle and build up, eventually causing blockages and SSOs (sanitary sewer overflows).
Beyond the raw data, city engineers are also checking that your as-built aligns with the approved construction drawings. Any deviation — a manhole moved 12 feet from plan, a pipe size changed, a connection point relocated — must be flagged, red-lined, and approved as a design change before as-built acceptance. Submittal packages that do not clearly call out deviations are a common rejection reason.
Turnaround expectations vary by municipality, but most expect a complete as-built within 30–60 days of project completion. Projects that go to final inspection without a complete as-built package can be held indefinitely from final acceptance, delaying retainage release and causing downstream issues with bonding and public works permit closeout.
The invert elevation documentation process runs in parallel with pipe installation — not after. Each time a sewer pipe run is installed and a manhole is set, the field crew captures four data points: the invert elevation at the incoming pipe (invert in), the invert elevation at the outgoing pipe (invert out), the horizontal distance between manholes (pipe run length), and the pipe diameter. From these four values, all derived quantities — slope percentage, velocity at full flow, and depth of cover — are calculated.
Field measurement of invert elevations requires a benchmark elevation from the project control network. The crew runs a level circuit from the nearest benchmark to the manhole, reads the rod on the invert of the pipe, and computes the elevation. On jobs with GPS-equipped survey instruments, the process is faster: set a RTK rover on the rim of the manhole, subtract the rim-to-invert measurement (rim-to-invert is measured with a tape), and record the invert elevation. The invert-to-invert difference divided by the pipe run length gives slope.
Common documentation errors at this stage include: not documenting the invert on both sides of a junction manhole (where two lines meet, each must be recorded), not recording the invert for stub-outs or future connections, and not logging the actual installed pipe size if it differs from plan. Each of these will cause a rejection at city review.
The most critical single document in the as-built package is the manhole schedule — a table listing every manhole by ID, its rim elevation, each invert elevation (in and out), the pipe size on each leg, and the GPS coordinate. When a city field inspector wants to verify an as-built before acceptance, they walk to a random manhole, pull the lid, drop a tape from rim to invert, and compare that measurement to the record. A 0.1-foot discrepancy in the record is flagged; a 0.3-foot discrepancy triggers a full re-verification.
Depth of cover documentation follows the same process but is measured at road crossings, high-traffic areas, and locations near structures. Most jurisdictions require 36 inches minimum cover over the crown of the pipe under roadways. Frost-depth requirements in cold climates may increase this to 48–60 inches in northern states. The field crew measures the crown elevation by adding half the pipe OD to the invert elevation, then subtracts from the ground surface elevation to determine cover. Every location with minimum cover is flagged in the as-built package.
Sitemark replaces the clipboard, the spreadsheet, and the three-day post-job data-entry marathon with a structured field data entry workflow that runs while the pipe goes in the ground. The app guides the field crew through every required data point at each manhole — invert in, invert out, pipe size, pipe material, depth of cover — and calculates slope and velocity automatically. Pass/fail against design grade appears immediately.
Each pipe run is linked to the structure IDs on both ends (MH-1 to MH-2, for example), matching the manhole numbering on the approved construction drawings. If a run fails to meet minimum slope, the app flags it before backfill — not during city review six weeks later. The crew can correct the grade, re-check the invert, and document the corrected run with a note in the same record. The full history is retained.
When the job is complete, Sitemark's one-click export generates a formatted PDF package that includes: a manhole schedule table (ID, rim elevation, all inverts, pipe sizes, GPS coordinates), a pipe run table (run ID, from/to MH, length, pipe size, slope, velocity), a depth-of-cover summary at flagged stations, an equipment register (pipe laser model, calibration date), and a summary signature block. This is the document format that city engineers recognize and accept.
Inspector share links allow the contractor to send the city engineer a read-only view of the as-built before the final walkthrough. The inspector can review the manhole schedule, check that all structures are documented, and identify any questions in advance — turning the final inspection into a five-minute confirmation rather than a discovery session. Projects using digital as-built submissions close 60–90% faster than those with hand-compiled packages.
For multi-crew projects, Sitemark's company plan allows multiple users to contribute to the same job simultaneously. Crew A logs MH-1 through MH-8; Crew B logs MH-9 through MH-14. The supervisor sees all entries in real time from a project dashboard. The final as-built pulls from all crew entries in one coherent, de-duplicated document.
Every manhole in the system must be documented. Skipping an intermediate structure leaves a gap in the slope record that the city cannot verify.
A list of invert elevations without calculated slope percentages forces the city engineer to do your math. Most engineers reject these outright.
Road crossings require documented depth of cover to verify minimum requirements. Missing coverage data at crossings is the #2 rejection reason.
GIS-based utilities management requires accurate coordinates. Coordinates copied from plan instead of measured as-installed are flagged at review.
Any pipe route, structure location, or size change from the approved plans must be flagged as a deviation. Undisclosed deviations result in full re-review.
Most municipalities require a contractor signature certifying the as-built data. Missing signatures prevent acceptance regardless of data quality.
City engineers typically require MH-to-MH invert elevations (in and out at each structure), pipe size and material at each run, slope percentage between each MH pair, depth of cover at road crossings, GPS coordinates of all manholes, rim elevations, and the contractor's signature certifying accuracy. Many municipalities also require deviations from the approved drawings to be explicitly noted. Sitemark generates a package covering all of these fields.
An MH invert elevation is the elevation of the inside bottom of a sewer pipe at a manhole. It determines the slope of the pipe run between two manholes. If the invert elevation is wrong — installed too flat or with reverse slope — the pipe will not drain at the required minimum velocity of 2 fps, leading to solids buildup and potential sanitary sewer overflow. Documentation errors at closeout mean the city cannot verify the system will perform as designed.
Sitemark generates a field-documentation as-built, not a licensed survey. Projects requiring a PE-stamped or licensed surveyor as-built still need a licensed professional. However, Sitemark's organized field data significantly reduces the time and cost for the surveyor because all invert elevations, pipe run data, and GPS coordinates are already captured and formatted — the surveyor verifies rather than re-collects.
Per IPC 704.1: 4-inch pipe = 1/4 inch per foot (2.08%) minimum; 6-inch pipe = 1/8 inch per foot (1.04%) minimum; 8-inch pipe = 1/16 inch per foot (0.52%) minimum. These minimums ensure self-cleaning velocity of at least 2 fps at full flow per ASCE MOP 36. Your municipality may have stricter requirements — always check local standards.
The most common rejection reasons are: missing invert elevations on intermediate manholes, slope not calculated between each MH pair, depth of cover not documented at road crossings, missing or inaccurate GPS coordinates, pipe size not confirmed at each run, and deviations from approved drawings not noted. Sitemark's structured data entry prevents all of these omissions.
Sitemark captures invert elevations, pipe run data, and depth of cover as you install — and generates the formatted package city engineers accept at first submittal.