MARTIN Lewis' MoneySavingExpert.com has issued a warning over a key household bill - and revealed tips on how to cut costs.
The consumer website said in its latest newsletter water bills are the "forgotten utility" but you can pay less through five tricks.
It comes as water bills rose by 6% on average in April across England and Wales.
Meanwhile, Thames Water, which serves 16million customers, plans to raise water bills by 56% over the next five years to help tackle a huge multi-billion pound debt pile.
Social tariffs and the WaterSure scheme
Social tariffs are available to households on certain benefits such as Universal Credit and cover broadband and mobile phones.
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But you can also get them for your water bills - and they can reduce your overall bill by up to 90%, MSE said.
Millions of households are missing out on social water tariffs and could save £160 a year on average.
You might also be able to cut costs via the WaterSure scheme.
You qualify if you have three or more children, or a medical condition such as Crohn's or eczema which means you need to use more water.
You also need to be on certain benefits such as Universal Credit and living in England or Wales.
If you qualify, you have your water bill capped at the amount of the average household water bill across your water company.
You can apply for the scheme via your water firm's website.
Freebies to cut water usage
Thousands of households in England, Wales, Scotland and Northern Ireland can claim free insulation and water-saving gadgets through their water companies.
You might be eligible for energy-saving shower heads, shower timers, garden hose nozzles and cistern bags which means your toilet uses less water each time it flushes.
The freebies are funded by water companies, but what you can get varies from firm to firm.
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Contact yours to see what help is on offer.
Water meters
MSE revealed how you can save £100s by installing a free water meter.
Water bills are based on an old system where the amount you pay is based on your home's rental value, not how much you use.
That means bigger homes tend to pay more even if they aren't going through that much water.
But, you can get a more accurate bill by getting a water meter installed, if you live in England or Wales.
MSE said, as a general rule, if you have more bedrooms in your home than people, you'll likely save money with a water meter.
The website went on to share a story of one reader who moved to a water meter and is now saving £1,128 a year.
You can get a water meter installed by contacting your water provider.
Switch your deal
If you live in a block of flats with shared pipes, you may be told by your water company you can't get a water meter installed.
But, you might be able to get an "assessed charge bill", which works out how much you would likely pay if you did have a meter put in.
If this bill comes out cheaper than your normal water bill, you can switch to it and save money moving forward.
Again, you have to go to your water company to ask about getting an assessed charge bill.
Sewerage rebates
If you've got a feature in the grounds of your home that means any water you've used isn't going back into the public sewerage system, you might be able to get a rebate.
If you've got a soakaway, pond, large garden or swimming pool, or cesspit or septic tank, you will likely qualify.
You can apply for rebates via your water company's website or via its customer services team.
If you've been refused a rebate, you can take your case to the Consumer Council for Water who might be able to claw back cash for you.
Do you have a money problem that needs sorting? Get in touch by emailing money-sm@news.co.uk.
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