Editable assumptions

Meter and tariff inputs

Choose a preset or switch to custom tariff and enter the charges from your bill.

Country or city preset

Currency

Usage mode

People, staff, or users served Used only for high-use warnings.

Billing period start

Billing period end

Previous meter reading (m3)

Current meter reading (m3)

Fixed charge

Sewerage or service charge

VAT or tax rate (%)

Actual bill amount (optional)

Leak suspicion toggle
Turn on if taps run overnight, the meter moves while closed, a toilet cistern leaks, or usage jumped suddenly.

Measured night-flow test (optional)

Close taps and water-using equipment, record the meter, wait, then record it again. Enter readings in m3; three decimals represent one litre.

Test start reading (m3)

Test end reading (m3)

Test duration (minutes) The projection assumes any measured movement continued for 24 hours/day; use it as a diagnostic ceiling, not a confirmed leak bill.

Tariff blocks

Custom rates

Blocks use cubic metres. Block 3 applies to all usage above the block 2 upper limit.

Block 1 upper limit (m3)

Block 1 rate per m3

Block 2 upper limit (m3)

Block 2 rate per m3

Block 3 rate per m3

All calculations run locally in your browser. Confirm final tariffs with your water utility or city authority.

Water bill result

Enter meter readings and charges to estimate consumption and expected bill.

Ready to calculate

Consumption - Meter difference in m3

Expected bill - Water, fixed, sewerage, and tax

Daily usage - Litres per day

High-use warning - Based on mode and users served

Bill breakdown

Block 1 charge	-
Block 2 charge	-
Block 3 charge	-
Fixed and sewerage	-
VAT or tax	-

Usage signals

Billing period	-
Per-user daily use	-
Actual bill variance	-
Leak risk	-
Next priority	-

Measured night-flow leak test

Add both optional test readings to quantify meter movement.

Meter movementNot entered

Measured flowNot entered

30-day loss ceilingNot entered

Variable bill impactNot entered

Leak checklist and next steps

The checklist updates from the reading, mode, usage level, and leak toggle.

Take a fresh meter photo and compare it with the current bill reading.
Check visible taps, toilet cisterns, storage tanks, and underground lines.
Confirm tariff block, fixed charge, tax, and sewerage/service charge with the utility.

Methodology

The calculation method rebuilds a utility-style water bill from meter consumption and tariff blocks.

Consumption = current meter reading - previous meter reading.
Tariff charge = block 1 usage x rate + block 2 usage x rate + remaining usage x block 3 rate.
Subtotal = tariff charge + fixed charge + sewerage or service charge.
Expected bill = subtotal + VAT or tax. Daily usage = consumption x 1,000 / billing days.
Night-flow test = meter change x 1,000 / test hours. The 30-day loss ceiling assumes that flow continued all day; bill impact reruns the tariff blocks with the projected extra m3 and adds tax.

Assumptions and sources

Presets are editable planning assumptions. They are not live official tariffs and may not match every suburb, customer class, subsidy, or meter plan.

Source data: current bill, meter readings, municipal tariff notice, city water utility schedule, and official authority updates.
Freshness note: reviewed 16 May 2026. Update the tariff blocks, fixed charge, tax, and sewerage charge when your provider changes rates.
Official check: confirm final amounts with your water utility, city authority, regulator, or consumer protection office.

Disclaimer

This is an estimate only. It does not replace an official bill, utility account ledger, licensed plumber inspection, municipal decision, or legal advice.

Tiered tariffs, minimum charges, communal meters, estimated reads, penalties, reconnection fees, and subsidies can change the result.
If a leak or billing dispute is serious, document readings and ask for the detailed account calculation before paying disputed charges.
For suspected contamination or unsafe water, use a water quality checker and contact the responsible authority.