Environmental Compliance, Waste & Water Management worked example
Water Discharge Cost at 72% billable discharge share: a worked example
Here is what the math looks like when conditions slip. We hold every other input steady and drop billable discharge share to 72%, then walk the calculation through step by step. Estimate water discharge cost from discharged water volume, discharge or sewer rate, applicable share, and fixed environmental fees.
The inputs for this scenario
- Discharged water volume: 1,850 kgal (held at the documented default)
- Discharge or sewer rate: 6.4 $ / kgal (held at the documented default)
- Billable discharge share: 72 % (the input this scenario stresses; the baseline uses 100)
- Fixed permit, meter, or account fees: 780 $ (held at the documented default)
Working through the calculation
- The calculation starts from the formula this tool documents: Variable cost = discharged water volume × discharge or sewer rate × billable discharge share.
- Total water discharge cost works out to 9,305 $ at these inputs, and this is the headline figure for the scenario.
- Discharge cost per kgal works out to 5.03 $ / kgal at these inputs.
- Variable water discharge cost works out to 8,525 $ at these inputs.
- Fixed permit, meter, or account fees works out to 780 $ at these inputs.
How this compares with the baseline
- Against the tool's baseline example, where billable discharge share sits at 100% and the headline result is 12,620 $, this scenario comes in 26.27% below the baseline at 9,305 $.
- The practical read: the gap between this scenario and the baseline is entirely attributable to billable discharge share, so recovering it is worth quantifying in dollars before considering equipment or staffing changes. It assumes a single flat volumetric rate; it does not model tiered/seasonal sewer blocks or surcharges for high BOD, TSS, or pH that many POTWs levy on top of the volume charge.
Results at a glance
- Total water discharge cost: 9,305 $ (headline result)
- Discharge cost per kgal: 5.03 $ / kgal
- Variable water discharge cost: 8,525 $
- Fixed permit, meter, or account fees: 780 $
Run it with your numbers
- To rerun this with your own numbers, open the live Water Discharge Cost calculator, set billable discharge share to your actual value, and adjust the remaining inputs to match your operation.
Last reviewed 2026-05-12.