Interactive Calculator · 2026
STP Water Balance Calculator
Map a building's water balance in one place — fresh supply in, sewage generated, treated water reused and the surplus discharged. See how much of your sewage a well-run STP puts back to work.
Sewage split: treated water reused vs discharged
Your water flows
Reuse is capped at the sewage you generate — you can only recycle water your STP actually treats. Anything treated but not reused is discharged.
Where your sewage goes
Of 160 KLD sewage, 130 KLD is reused and 30 KLD is discharged.
Every kilolitre you reuse is a kilolitre of fresh water you don't have to buy — and a kilolitre less treated effluent leaving the site. Pushing the reuse share up is the single biggest lever on a building's water cost.
The surplus that cannot be reused is discharged, and by law it must meet treated-water standards first.
How this is calculated
- Reuse = min(reuse entered, sewage) = min(130, 160) = 130 KLD.
- Discharge = max(0, sewage − reuse) = max(0, 160 − 130) = 30 KLD.
- Net fresh demand = max(0, supply − reuse) = max(0, 200 − 130) = 70 KLD.
- Reuse % = reuse ÷ sewage × 100 = 130 ÷ 160 × 100 = 81.3 %.
A concept-level water balance for planning. A detailed audit must also account for line losses, evaporation and seasonal variation — confirm with a qualified consultant before design.
Related Guides — Deep-dive reading
STPs and the Urban Water Circular Economy: How Reuse Closes the City Water Loop
How decentralised sewage treatment and treated-water reuse turn a building's wastewater into a resource — cutting freshwater demand, ending pollution at source, and pointing the way to a genuinely water-circular Indian city.
Sewage Treatment PlantsRajasthan STP Guidelines & RSPCB Norms: The 2026 Compliance Guide
When a sewage treatment plant is mandatory in Rajasthan, how the RSPCB consent process (CTE and CTO) works, what the discharge and reuse rules demand, and how owners and RWAs in Jaipur, Jodhpur and Udaipur stay compliant in India's most water-scarce state.
Sewage Treatment PlantsSTP for Shopping Malls: Mixed Loads, Big Reuse
Why a mall's wastewater is unlike any other building's — a punishing mix of food-court grease, washroom peaks and huge cooling-tower thirst — and how to size, site and choose an STP that turns all of it back into usable water in the basement.
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