Water Bill Calculator Sri Lanka 2026
Estimate your NWSDB water bill from monthly usage in m³. See slab charges and the service fee, with domestic and commercial options.
Rates verified current
Verified 25 Sept 2026 · source
Usage
Check your meter or last bill for monthly m³
Domestic tariff (reference)
| Range (m³) | Rate (Rs.) | Service (Rs.) |
|---|---|---|
| 0-5 m³ | 50 | 300 |
| 6-10 m³ | 70 | 300 |
| 11-15 m³ | 90 | 300 |
| 16-20 m³ | 100 | 400 |
| 21-25 m³ | 120 | 500 |
| 26-30 m³ | 150 | 600 |
| 31-40 m³ | 170 | 1500 |
| 41-50 m³ | 195 | 3000 |
| 51-75 m³ | 225 | 3500 |
| 76-100 m³ | 250 | 4000 |
| Over 100 m³ | 280 | 4500 |
Bill Estimate
Rs. 1,950
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Slab Breakdown
- Block 1 · 1–5 m³Rs. 50.00/m³5 of 5 m³ used5 × Rs. 50.00 = Rs. 250
- Block 2 · 6–10 m³Rs. 70.00/m³5 of 5 m³ used5 × Rs. 70.00 = Rs. 350
- Block 3 · 11–15 m³Rs. 90.00/m³5 of 5 m³ used5 × Rs. 90.00 = Rs. 450
- Block 4 · 16–20 m³your usage ends hereRs. 100.00/m³5 of 5 m³ used5 × Rs. 100.00 = Rs. 500
- Block 5 · 21–25 m³Rs. 120.00/m³not used
- Block 6 · 26–30 m³Rs. 150.00/m³not used
- Block 7 · 31–40 m³Rs. 170.00/m³not used
- Block 8 · 41–50 m³Rs. 195.00/m³not used
- Block 9 · 51–75 m³Rs. 225.00/m³not used
- Block 10 · 76–100 m³Rs. 250.00/m³not used
- Block 11 · 101+ m³Rs. 280.00/m³not used
- 1 more units → next band (total Rs. 2,170)
- 10 fewer units saves Rs. 1,050
Example: Domestic consumer using 20 m³
Sample Inputs
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Data updated August 2024 (Gazette 2398/19)
Current NWSDB Domestic Water Tariff (Gazette 2398/19)
The National Water Supply & Drainage Board applies the block tariff shown for the selected category (Gazette Extraordinary No. 2398/19, effective 21 August 2024). Domestic uses progressive block rates; Samurdhi recipients & tenement gardens have their own cheaper table; commercial premises pay a flat Rs. 150/m³ with a stepped service charge.
| Consumption Block (m³/month) | Unit Rate (Rs./m³) | Service Charge (Rs./month) | Typical Monthly Bill |
|---|---|---|---|
| 0-5 m³ | Rs. 50 | Rs. 300 | ~Rs. 550 |
| 6-10 m³ | Rs. 70 | Rs. 300 | ~Rs. 900 |
| 11-15 m³ | Rs. 90 | Rs. 300 | ~Rs. 1,350 |
| 16-20 m³ | Rs. 100 | Rs. 400 | ~Rs. 1,950 |
| 21-25 m³ | Rs. 120 | Rs. 500 | ~Rs. 2,650 |
| 26-30 m³ | Rs. 150 | Rs. 600 | ~Rs. 3,500 |
| 31-40 m³ | Rs. 170 | Rs. 1,500 | ~Rs. 6,100 |
| 41-50 m³ | Rs. 195 | Rs. 3,000 | ~Rs. 9,550 |
| 51-75 m³ | Rs. 225 | Rs. 3,500 | ~Rs. 15,675 |
| 76-100 m³ | Rs. 250 | Rs. 4,000 | ~Rs. 22,425 |
| Over 100 m³ | Rs. 280 | Rs. 4,500 | ~Rs. 22,425+ |
* Rates are from NWSDB Gazette Extraordinary No. 2398/19 (21 August 2024): Table 01 for Samurdhi & tenement gardens, Table 02 for other domestic consumers, Table 08 for commercial premises. Religious, government, school, hospital, shipping and bulk categories use separate gazette tables — verify yours at waterboard.lk. Sewerage charges, where applicable, are billed separately and are not included here.
Also estimating your monthly utility costs? Use our CEB electricity bill calculator to get a complete picture of your water and electricity expenses together. For vehicle owners, our fuel cost calculator helps estimate monthly petrol and diesel spending. Buying or transferring property? Use our Sri Lanka stamp duty calculator to budget for deed duty, and use the vehicle import tax calculator if you are importing a car.
What This Calculator Does
This calculator estimates your monthly water bill based on NWSDBNational Water Supply and Drainage Board — state water utility tariff slabs. Enter your consumption in cubic meters to see the breakdown of charges.
- Calculates bills using NWSDBNational Water Supply and Drainage Board — state water utility slab rates
- Shows usage and service charges separately
- Displays slab-by-slab breakdown with your position in the blocks
- Warns when a few m³ push you into a pricier block
- Supports domestic, Samurdhi/tenement-garden and commercial categories
Inputs and Assumptions
Assumptions
- - NWSDBNational Water Supply and Drainage Board — state water utility Gazette Extraordinary No. 2398/19 (21 August 2024): domestic Table 02, Samurdhi Table 01, commercial Table 08
- - Standard metered connection — no arrears, rebates or VATValue Added Tax — consumption tax charged at each stage of sale adjustments
- - Sewerage surcharge, where applicable, is billed separately and excluded
- - Monthly billing cycle
Frequently Asked Questions
Related Resources
Sources & methodology
Part of the Utilities & Rates collection
How we calculate
National Water Supply & Drainage Board
Get utilities & tariffs change alerts
Methodology verified 2026-09-30 against National Water Supply & Drainage Board · Attribution: CalcLK
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