Every Service AI run that designs a sanitary (wastewater) network produces a capacity table: one row for every proposed pipe, showing its size, levels and cover, the dry weather and wet weather flows it carries, and where the water surface sits at the design flow. A Checks column flags the pipes that need attention.

Where to find it

In Civil 3D — Tools panel ▸ Servicing ▸ Sanitary Capacity opens the table in a pane.

In the Allsite.ai web app — Design ▸ Design data ▸ Sanitary capacity, for the project's latest results.

The Allsite.ai web app sidebar for a project. The Design group is expanded, and inside it Design data lists Cutfill, Schedule of Quantities, Lot report, Road report, Storm capacity and Sanitary capacity. Sanitary capacity is outlined.

As a spreadsheet — the download button saves the full capacity workbook for each subnet (a menu lists WW01, WW02 and so on). The workbook contains the full formulae, so it can be reviewed in detail (see below). Where no workbook is available it saves the table as a CSV instead.

Before you read the numbers

One row is one pipe. The table is a Summary followed by one table per subnet (WW01, WW02 …), downstream pipe first.
Check the units. They sit in each column heading — m, m RL and m³/s on a metric project; ft, ft RL and ft³/s on an imperial one. Flows are in cubic metres or cubic feet per second, not litres.
Flows are shown to three decimal places. Sanitary flows are small, so a value can look coarse or round to 0.001. The spreadsheet carries the full values.
The table has the same layout as the storm table for the pipe, levels and cover columns. See Interpreting Storm capacity table data for those; this article covers what differs.

The Sanitary capacity page. A Summary table counts pipes and checks. Below it the WW01 table lists four pipes with their size, grade, inverts and cover.

The Summary and the left-hand columns of WW01. Numbered markers: 1 Pipe, 2 Downstream link, 3 Diameter / width, 4 Grade, 5 US invert, 6 US cover.

Dry weather and wet weather flows

Three flow columns build on each other. Each pipe carries its own load plus everything upstream of it.

Column	What it is
ADWF	Average dry weather flow: the everyday flow from the buildings that discharge to this pipe and every pipe upstream.
PDWF	Peak dry weather flow: ADWF multiplied by the DWF peaking factor setting.
PWWF	Peak wet weather flow: PDWF multiplied by the WWF peaking factor setting.
Design flow	The flow the pipe is checked against. For a sanitary network it is the PWWF.

The two peaking factors multiply. With the default settings (DWF peaking factor 2.5, WWF peaking factor 4.0), PDWF is 2.5 times the ADWF and PWWF is 4.0 times the PDWF, so the PWWF, and therefore the Design flow, is 10 times the ADWF. If you change either factor, the PWWF changes by the product of the two.

The flow columns of the WW01 sanitary table: ADWF, PDWF, PWWF, design flow, velocity, US and DS HGL, minimum freeboard and Checks. Pipe 3 is marked Cover below minimum.

The flow columns of WW01. Numbered markers: 1 ADWF, 2 PDWF, 3 PWWF, 4 Design flow, 5 Minimum freeboard, 6 Checks.

Where the load comes from. Each building with a sanitary connection contributes a daily load. If the building has none set, it is taken from the Default sanitary flow calculation parameters table: the number of people for the building's bedroom count multiplied by the litres per person per day. Change that table, the bedroom counts or the number of buildings and the flows change with them.

Velocity, water levels and freeboard

Column	What it is
Velocity	How fast the water moves through the pipe at the design flow.
US HGL, DS HGL	The level of the water surface at each end of the pipe at the design flow.
Minimum freeboard	How far the water stays below ground at its worst end. Negative means the water level is above ground.
US cover, DS cover	Ground level minus the top of the pipe — the depth of earth over the pipe's crown.

Reviewing the workings in the spreadsheet

The table is a summary. The spreadsheet you download from the same button is the full capacity assessment for each subnet, and it contains the formulae, not just the results, so you can follow every number back to its inputs and review it in detail.

One workbook per subnet (WW01, WW02 …). Click into a cell and the formula shows how the value was worked out from the pipe's levels, size, roughness and flows.
The capacity assessment sheet lays the pipes out one per column, downstream first, with more rows than the table shows, including the node, catchment and head loss working behind the water levels.
The supporting reference data, such as the rainfall and coefficient tables the formulae look up, is on a second sheet.
Change an input in the workbook and the dependent cells recalculate, which is useful for checking a result or testing a what-if outside Allsite. It does not change your Allsite design.

Use the spreadsheet when you need to explain a result to a reviewer, check one pipe by hand, or see detail the table leaves out.

Checks

Check	What triggers it	What to do
Overflow	The water level at either end is higher than the ground.	The pipe cannot carry the design flow without surfacing. Increase its size or grade.
Surcharged	The water level is above the top of the pipe, but not above the ground.	The pipe is running under pressure at the design flow. Check Minimum freeboard and your standards.
Cover below minimum	Ground minus (invert plus the pipe's outside diameter) is less than the required cover at either end.	Lower the pipe or raise the ground. The requirement comes from the carriageway cover under roads and the other-area cover elsewhere.
Pipe clash / Clearance below minimum	Two unconnected pipes cross with no gap, or less than the required clearance.	Both pipes are flagged. Change the level of one.
Pipe/structure clash, Structure clearance below minimum, Pipe under/over structure	A pipe passes through, too close to, or directly above or below a structure.	Move the pipe or the structure.

A blank Checks cell is only meaningful if the cover and clearance review ran. If the Summary has no cover or clearance rows, only the Overflow and Surcharged checks were applied.

Settings that change these numbers

Setting	What it changes
DWF peaking factor, WWF peaking factor (Capacity assessment)	PDWF, PWWF, the Design flow, and so on every velocity, HGL and check.
Default sanitary flow calculation parameters	The load of buildings that have none set: occupancy per bedroom count and litres per person per day.
Buildings and bedroom counts, lot sanitary connections	ADWF.
Pipe catalogue, levels and grades	Geometry, velocity and HGL.
Carriageway cover, Other area cover and the clearance table	The Cover and Clearance checks.
Project units	Every unit in the table.

These settings are described in Storm / Sanitary Networks.

Common questions

The page says “No Sanitary capacity data”.
No sanitary results have been imported for this project yet, or the latest Service AI run designed no sanitary network. Run Service AI and import its results.

The table does not match my latest design.
It shows the last Service AI results that were imported. If the latest run finished as not viable, the previous run's table is kept.

Why do ADWF, PDWF and PWWF not look like exact multiples of each other?
Each is rounded to three decimal places for display. Use the spreadsheet for full precision.

Where are the manholes and catchments?
In the spreadsheet. The table shows pipes only.

The Storm / Sanitary Networks article describes the network settings behind these results. For the equivalent table for stormwater pipes, which adds the catchment and inlet columns, see Interpreting Storm capacity table data. Contact the Allsite.ai support team if a value does not look right for your site.

Interpreting Sanitary capacity table data