Select a fixture or equipment connection, identify its system, and trace it through the floor plan, riser, related levels, and receiving connection. Reconcile tags, pipe descriptions, flow direction, elevation references, and access information. Record missing evidence separately from a confirmed document disagreement.
Gather the system descriptions and receiving information
Collect plumbing floor and roof plans, risers or isometrics, fixture and equipment schedules, water-heater details, specifications, and relevant civil utility information. Add architectural room layouts and sections where they affect fixtures, shafts, or access. For alterations, include available records of the existing system and identify which connections remain unverified.
Keep domestic water, sanitary drainage, venting, storm drainage, and specialty systems distinct. A line crossing another line on a plan does not necessarily show a connection. Use the legend and system references to interpret the drawing. Escalate an ambiguous symbol rather than inventing connectivity.
Phoenix publishes separate IPC and UPC plumbing checklists. Its IPC plumbing checklist, revised August 2025, references the 2024 IPC with local amendments. That distinction matters: choose the code family and edition governing the project before assessing technical criteria. The original checklist below organizes document questions without adopting Phoenix’s requirements nationwide.
Twelve plumbing document checks
Start with a vertical stack or a complete equipment connection and record the levels included. Expand the review to repeated stacks only after checking whether their layouts differ. The CSV provides blank project, source, criteria, ownership, decision, and closure fields for each prompt.
| Review area | Sources to compare | Question to resolve |
|---|---|---|
| System identity | Legend, floor plans, riser labels | Are domestic water, sanitary waste, vent, storm, and specialty systems distinguishable at each reference? |
| Fixture mapping | Fixture tags, schedule, enlarged plans | Does each fixture connect to the intended services and retain the same identity across the drawings? |
| Stack continuity | Floor plan branch, riser node, plans above/below | Can the same stack and its branches be followed across levels without unexplained additions or disappearances? |
| Water distribution | Water entry, distribution diagram, fixture/equipment demand references | Do the sources describe the same supply arrangement and demand inputs for the designer to verify? |
| Hot water return | Heater detail, hot-water/return plans, control notes | Are the flow path, return connection, and stated operating controls consistently described? |
| Drainage levels | Drainage plan, invert notes, sections, site connection | Are flow direction and elevation references sufficient to investigate the route to its receiving connection? |
| Vent references | Fixture branch, vent diagram, termination detail | Can the described vent arrangement be traced to its termination and applicable design review? |
| Indirect discharge | Equipment requirement, receptor detail, drain destination | Is the receiving arrangement identified, with required protection and connection method assigned for review? |
| Roof drainage | Roof plan, drain tags, storm diagram, discharge notes | Do primary and secondary drainage descriptions remain identifiable through their stated destinations? |
| Protection devices | Water-service diagram, device schedule, access notes | Are the specified backflow or other protective devices represented consistently and located for review? |
| Access and penetrations | Cleanouts/valves, wall/ceiling layouts, opening details | Are access needs and structural openings acknowledged in the receiving drawings? |
| Existing tie-ins | Existing survey, demolition scope, proposed connections | Is each tie-in confirmed or explicitly awaiting verification, with a responsible person and follow-up? |
Specialty systems such as medical gas, laboratory waste, or treatment equipment need their own design expertise and references. Mark them as a defined separate scope instead of treating a generic plumbing row as a complete review.
Read a riser together with its floor plans
A riser diagram shows system relationships, while floor plans locate the work. Start at a fixture or branch, note its stack identifier, and find the same identifier on the riser. Follow it through the levels above and below. Compare branch descriptions and termination references without expecting a schematic diagram to reproduce the plan geometry.
For drainage, read elevations and direction together. An invert level describes a different point from a finished-floor level. If the package does not establish the datum or slope information needed to assess a route, ask for that missing basis. Do not infer a buildable slope from the apparent angle of a schematic line.
Trace discharge all the way to the stated receiving system. An equipment note that says “drain by others” leaves a coordination decision open unless the receiving connection and responsible designer are identified. Compare the equipment requirement with the receptor or connection detail and ask the plumbing designer to confirm the appropriate arrangement.
Worked example: a stack stops at the wrong level
Hypothetical example. A second-floor plan shows fixture group FG-2 connected to waste stack W-3. The W-3 riser stops at the first floor, and the second-floor riser branch is labeled W-4. The package contains no note explaining a transfer between stacks.
FG-2 connects to W-3 on the second-floor plan, but the riser shows that branch at W-4 and ends W-3 below it. Please confirm the intended stack and branch arrangement, then identify the plan, riser, and affected level details to revise.
The plumbing designer must resolve the connection and assess any sizing or venting consequences. If a shaft or slab penetration changes, coordinate that decision with architecture and structure. Closure requires consistent revised plans and riser references, plus a recorded status for the receiving opening. Relabeling the branch alone may leave the physical route unresolved.
Record what a drawing review cannot establish
Existing pipe capacity, concealed routing, and actual tie-in elevations may require investigation beyond the supplied PDFs. Keep those items in the review record with an owner and required evidence. A field-verification note should identify the uncertain condition and what decision depends on it.
Likewise, matching pipe sizes across sheets does not validate hydraulic performance or drainage design. Ask the responsible engineer to review calculations when inputs or routes change. Backcheck water-heater controls, hot-water return descriptions, or roof-drain destinations affected by the response. Use the MEP checklist to carry access, power, and structural opening decisions across disciplines.
Use Groundbook to investigate plumbing references
Groundbook can review supplied plumbing drawings, schedules, specifications, reports, and uploaded criteria to identify potential inconsistencies with source links. The reviewer verifies each connection and assigns the decision. The software does not certify hydraulic calculations, inspect concealed work, or establish permit approval.
Explore within-discipline drawing review or start with a plumbing document package.