Help With Your Water Bill

£350.16

The lowest cap here, on HelpU

Average household bill this year: £683.00

What your water and sewerage should cost this year at Welsh Water's published rates, and the three capped tariffs that can bring it down.

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The published charges

Dŵr Cymru Welsh Water — Charges for 1 April 2026 – 31 March 2027.

Welsh Water supplies both the water and the sewerage for Merthyr Tydfil, so one company sets both halves of the bill. It has no shareholders, and every figure below is one it published itself for this charging year.

£683.00

Average household bill this year (2026-27)

Up from £652.00, a rise of 4.8%. Welsh Water's own figure for an average household across every kind of charge. It hides a lot: the company puts the rise on metered bills at about 6.2% and on unmeasured bills at about 9.7%. It is also only an average — what you pay depends on how your home is charged, not on this number.

If you have a meter

	Water	Sewerage
Service charge for the year	£58.63	£151.74
Per cubic metre	£1.9527	£2.7418
No surface-water drainage — Service charge for the year	—	£105.87

Sewerage is not charged on all the water you use. Welsh Water charges it on 95% of the metered volume, on the assumption that the other 5% goes on the garden or into a kettle and never reaches the sewer. The lower sewerage service charge is for a property with no surface-water drainage — rainwater from your roof and yard soaking away on your own land rather than running into the public sewer. If a bill spans 1 April, the part before that date is charged at last year's rates.

If a meter cannot be fitted

Where a meter cannot be fitted — which covers a lot of flats and some older terraces — Welsh Water charges an assessed amount instead. It is a flat yearly figure set by how many people live there, and it is not metered, so using less water does not bring it down. Band A is the company's average-use table and Band B its low-use one; which of them you are put on is the company's decision, not a choice.

Band A — average use

What Welsh Water treats as average household use.

People	Volume assumed	Water	Sewerage	No surface-water drainage
0	0 m³	£58.63	£151.74	£105.87
1	65 m³	£185.56	£321.04	£275.17
2	92 m³	£238.28	£391.37	£345.50
3+	124 m³	£300.76	£474.72	£428.85

Band B — low use

What Welsh Water treats as low household use.

People	Volume assumed	Water	Sewerage	No surface-water drainage
0	0 m³	£58.63	£151.74	£105.87
1	49 m³	£154.31	£279.37	£233.50
2	72 m³	£199.22	£339.28	£293.41
3+	100 m³	£253.90	£412.21	£366.34

If you have no meter

A home with no meter is charged on its rateable value — a valuation made before 1990 and never updated since, which is printed on your bill. The charge is a standing charge plus an amount for every £1 of that value. Welsh Water also publishes a flat Uniform Service Charge; ask the company which of the two applies to your home. Unmeasured bills went up about 9.7% this year, which is the steepest rise on the list, so it is worth asking whether a meter would leave you better off — and you can ask for one to be fitted.

	Water	Sewerage
Service charge for the year	£188.57	£311.65
No surface-water drainage — Service charge for the year	—	£241.35
Per £1 of rateable value	£1.6448	£2.4711
Uniform Service Charge	£402.39	£632.90
No surface-water drainage — Uniform Service Charge	—	£562.60
Surface-water and highway drainage only	—	£84.18

Not charged where the rateable value is £25.00 or less

Help With Your Water Bill

About these tools

What your water costs this year

What does not count as income

The benefits these caps ask about

The caps in full

HelpU

Household income must be at or under

What rules it out

If you are behind

Customer Assistance Fund

How it works

Who it is for

If a bill has become impossible

Cymuned

Apply through

The published charges

If you have a meter

If a meter cannot be fitted

The company’s own pages

Bill Cap — WaterSure Wales

And one of these

What rules it out

Welsh Water Assist – Transition

Band A — average use

Band B — low use

If you have no meter