Your Water Cost
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Water Cost Calculator
On a water meter? Enter your rates from your bill and your monthly usage in m³ to see your exact water cost broken down per litre, per day, per month and per year — plus what that usage actually means in real terms.
Tip! — Find your water unit rate (£/m³), sewerage rate (£/m³) and standing charges on your water bill. Thames Water 2026/27 defaults are pre-filled — update them with your own rates for an exact result.
Your Rates
Enter the rates from your latest water bill. Your water company's rates are shown on the charges page of your bill or on their website.
| Charge | Your Rate |
|---|---|
| Water supply rate (£/m³) | |
| Sewerage / wastewater rate (£/m³)
Applied to 95% of supply usage |
|
| Water supply standing charge (£/year) | |
| Sewerage standing charge (£/year) |
Your Usage
Enter your usage in cubic metres (m³). You'll find this on your water bill between the two most recent meter reads. Not sure? Use the estimate by household size option.
| Usage | Amount |
|---|---|
| How would you like to enter usage? | |
| Monthly usage (m³) |
Full Cost Breakdown
| Item | Monthly | Annual |
|---|---|---|
| Run calculation to see breakdown | ||
What Does Your Usage Look Like?
Based on your monthly usage — what this volume of water represents in everyday terms.
Cost Per Litre
GUIDE
How to Read Your Water Bill
A plain-English walkthrough of every charge on a metered water bill — what each line means and where to find your rates.
Read Guide →How to Use This Calculator
- Enter your rates — find your water supply rate (£/m³), sewerage rate (£/m³), and standing charges on your bill or your water company's charges page. Thames Water 2026/27 rates are pre-filled as a starting point.
- Enter your usage — choose how you want to enter your usage: monthly m³ from your bill, annual m³, or let the tool estimate based on household size.
- Click Calculate — see your cost per litre, per day, per week, per month and per year, plus a breakdown of each charge component.
Where to Find Your Rates
Your water bill will show your volumetric unit rates (the amount charged per m³ of water) and your standing charges (the fixed annual amounts). These are usually on a charges summary page, or on the back of a paper bill. Most water company websites also publish their current tariff schedules.
Why Sewerage Is Charged on 95% of Usage
Water companies apply sewerage charges to 95% of your metered water supply, not 100%. The 5% discount reflects the assumption that a small proportion of water used outdoors — for garden watering, car washing — does not return to the sewer network. This is a standard industry assumption used across England and Wales.
UK Metered Water Rates 2026/27
Rates vary significantly by water company. These are confirmed figures for 2026/27 from company tariff schedules:
| Water Company | Water rate (£/m³) | Sewerage rate (£/m³) | Standing charges (£/yr) |
|---|---|---|---|
| Thames Water | £2.7346 | £1.4721 | £195.00 |
| Severn Trent Water | ~£2.10 | ~£1.70 | ~£150 |
| United Utilities | ~£2.73 | ~£2.08 | ~£130 |
| Anglian Water | ~£2.90 | ~£1.90 | ~£165 |
| Yorkshire Water | ~£2.25 | ~£1.95 | ~£145 |
| South West Water | ~£3.60 | ~£2.50 | ~£165 |
| Northumbrian Water | ~£1.85 | ~£1.55 | ~£125 |
Approximate figures only for non-Thames companies — enter your actual rates from your bill for an exact result. South West Water rates are the highest in England; Northumbrian Water among the lowest.
Frequently Asked Questions
How do I calculate my metered water bill?
Multiply your m³ usage by your water supply rate, then add your sewerage rate applied to 95% of your usage, then add your annual standing charges divided across the billing period. This tool does the full calculation — just enter your rates and usage from your bill.
What is the average water rate per m³ in the UK?
UK metered volumetric rates vary by company. Combined water and sewerage rates in 2026/27 range from around £3.40/m³ (Northumbrian Water) to over £6.10/m³ (South West Water). Thames Water charges £4.21/m³ combined. Always use the rates on your own bill for an accurate result.
How many litres is 1 cubic metre of water?
One cubic metre (1 m³) equals exactly 1,000 litres. That is roughly 25 quick showers, 12 full baths, or 14 washing machine loads on a standard cycle.
What is a sewerage charge on a metered bill?
Sewerage charges cover the collection and treatment of wastewater leaving your home. On a metered bill, they are calculated as a rate per m³ applied to 95% of your water supply usage — the assumption being that 5% of water used outdoors does not return to the sewer. The sewerage charge is often comparable in size to the water supply charge itself.
What is the standing charge on a metered water bill?
Standing charges are fixed annual amounts that cover infrastructure maintenance and billing costs, paid regardless of usage. Thames Water's combined standing charge is £195/year from April 2026. These are typically split between a water standing charge and a sewerage standing charge on your bill.