Martin Lewis' Money Saving Expert (MSE) website has urged millions to check if they can claim £160 worth of help for household bills.
The recent MSE newsletter highlighted that "millions" were missing out on the extra support for their water bills.
The MSE newsletter said: "Water's often the forgotten utility, but the bill certainly isn't forgotten, with it being £100s for most and over £1,000 a year for some.
"While water firms are privatised - so there's no competition and you can't switch provider - there are still loads of other ways you can try to cut the bill."
One of the ways you can cut costs is through social water tariffs.
The newsletter added: "Social tariffs are offered by all firms and can reduce what you pay by up to 90%.
"There are 5.7million ELIGIBLE HOUSEHOLDS MISSING OUT on an estimated £160 a year on average."
Social tariffs are available from every single water supplier in the UK and are usually cheaper options for those who are on a low income.
However, there is no blanket definition of who is eligible for support so it does vary depending on the water supplier.
For South East Water, if your level of income is below £18,005 then you may be able to be accepted onto their social tariff.
For Southern Water, being on the social tariff can cut your bill by a minimum of 45% all the way up to 90% - Severn Trent also offers a 90% cut on bills for those on low-incomes.
To find out exactly what your water company is offering you can find out by visiting their website.
To be put on a social water tariff you will need to contact your water provider.
Alongside social tariffs, water companies also offer grants worth hundreds of pounds to help with rising costs.
The exact amount you can get depends on where you live and your supplier, as well as your individual circumstances.
The water industry body, Water UK says there is also further targeted support for low-income customers who use a lot of water for essential family or health reasons through the WaterSure scheme.
Water UK highlighted that unlike other utilities such as energy, household water customers will "never be disconnected for non-payment of bills".
