Peer review — formally reviewing another engineer's plans before submission to the agency — is one of the most effective ways to reduce plan check comments and catch errors before they become expensive. But a peer review is only as good as the reviewer's method. Looking at the plans casually and saying "looks good" is not a review. A systematic approach that checks specific items in a defined sequence catches the issues that matter.

Third-party plan review by a licensed PE is a common form of civil engineering subconsultant services for projects that need an independent check before agency submittal.

The Review Sequence

Start with the big picture and work down to the details. The following sequence covers the critical items for a site civil plan set:

1. Overall Site — Does the Layout Work?

  • Does the site plan match the tentative map or approved entitlement? Are the building footprints, parking counts, and access points consistent with the conditions of approval?
  • Are the setbacks correct? Check front, side, and rear setbacks against the zoning code.
  • Does the parking count meet code? Count the stalls, check the sizes (standard, compact, accessible), and verify the ratio.
  • Is there adequate turning radius for the design vehicle? Garbage trucks and fire apparatus need specific turning radii (typically 25- to 28-foot inside radius for fire apparatus). Check every dead-end and every tight corner.

2. Drainage — Where Does the Water Go?

  • Trace the drainage from every high point to its outlet. Every square foot of the site should drain to a defined collection point.
  • Check for low points without inlets. If a proposed contour creates a low point, there must be an inlet or a drainage path out.
  • Verify that the building pad has positive drainage away from the foundation. 2% minimum for the first 10 feet.
  • Check that storm drain pipe sizes and slopes are adequate for the contributing drainage area. Run a quick rational method check on the critical pipe runs.
  • Verify that the stormwater treatment facility (bioretention, etc.) is properly sized and has an overflow path.

3. Accessibility — Does the ADA Route Work?

  • Trace the accessible route from every accessible parking space to the building entrance it serves. Check running slope (5% max) and cross-slope (2% max) at every segment.
  • Check every driveway crossing. The sidewalk cross-slope at the driveway must not exceed 2%.
  • Verify curb ramp geometry: landing size (48"x48" min), ramp slope (8.33% max), flare slopes (10% max), truncated dome placement.
  • Check accessible parking stall dimensions, slopes (2% max in any direction), and signage.

4. Fire Access — Will the Fire Marshal Approve?

  • Fire access road width: 20 feet minimum (26 feet where aerial apparatus access is required).
  • Fire access road within 150 feet of all portions of the building exterior (or per local code).
  • Dead-end fire lanes: turnaround required (hammerhead, cul-de-sac, or approved alternative).
  • Hydrant spacing and fire flow per the applicable appendix.
  • Knox Box and FDC locations shown and accessible from the fire lane.

5. Utilities — Do the Connections Work?

  • Sewer lateral: adequate slope (2% min), adequate depth to connect to the main, no conflicts with other utilities at the crossing points.
  • Water service: adequate size for domestic and fire demands, backflow prevention device located per the water district standards.
  • Storm drain: pipe slopes, inlet rim elevations, and outfall elevation all consistent.
  • Joint trench: conduit sizes, separations, and vault locations per the utility company standards.

6. Details — Are They Complete and Correct?

  • Do all sections and details referenced on the plan sheets actually exist in the detail sheets?
  • Are the standard details the correct version for the jurisdiction? (Using a city's 2015 standard detail when the 2023 version has been adopted is a common error.)
  • Are the notes complete? Grading notes, utility notes, pavement notes, erosion control notes — check that all required notes are present.
  • Do the plan and profile match? Verify that the plan view pipe alignments and elevations are consistent with the profile view.

What a Peer Review Is Not

A peer review is not a stamp review (signing and sealing someone else's plans without independently verifying the design). It is not a code check (verifying every code requirement — that is the plan checker's job). And it is not a replacement for QA/QC within the design firm. The peer review catches the issues that the design team is too close to the project to see.

A thorough peer review of a typical commercial site plan takes 4 to 8 hours. It adds a few hundred to a few thousand dollars to the project cost. It saves weeks of plan check re-review time and prevents construction-phase corrections that cost orders of magnitude more.