How the estimate is built
NCWSC (Nairobi Water) bills residential consumers using a WASREB-approved block tariff: a small lifeline block priced below cost, then progressively higher rates as consumption climbs. Your total bill is the sum of water charge across all blocks you traverse, plus a fixed monthly standing / meter charge, plus a sewer surcharge (typically 75 percent of the water charge) if your property is connected to sewer.
What the estimator does not include
- Water resource use levy (WSTF cess), charged on some tariff schedules at KES 0.50 per m³.
- Any pollution or effluent levy the county has approved on top of the base tariff.
- Outstanding arrears from prior months carried into this bill.
- Reconnection fees where the account was previously disconnected.
When the estimator is wrong
The tariff bands modelled here are indicative and may be one WASREB review behind the current approved schedule. If your bill differs from the estimate by more than 15 percent, request the current tariff schedule from NCWSC (Nairobi Water) customer care (0722 200 355 / 0733 620 620) or check wasreb.go.ke → My Tariffs.