If you don't have a water meter, you pay a fixed price for your water. It doesn't matter how much water you use, your bill won't change. Instead, the bill is based on the "rateable value" of your home - aka, how fancy it is.
Some people pay less with a meter, some don't. It all depends on your own situation.
Live alone, as a couple or small family, in a valuable home? Bingo! You might well save money with a meter.
Shedloads of kids in a small space? Dishwasher/washing machine/shower/garden sprinkler on all the time? Watch out. A meter might be more expensive.
Here's our quick step-by-step guide to help you work out what's best for you and your home.
How to switch to a water meter
You'll need to know who provides your water, which can be found on your water bill.
Check if a meter might be cheaper
First, check if a meter might be cheaper.
Dig out your bill, then contact your supplier or bung some figures into the Water Meter Calculator helpfully provided by the Consumer Council for Water.
As a rule of thumb, if there are fewer people living in your home than bedrooms, you should save money with a water meter
Get a meter fitted for free
Good news if you live in England or Wales - you can get a meter fitted for free.
Contact your water company to see if you would save, then fill in a quick application form by phone, post or online.
Sorry Scotland – you may need to pay £300 plus for installation costs.
Expect a survey
The water company will show up to see if it is possible to fit a meter. If so, it should fit it within three months.
Your water company will choose where to put the meter, whether inside or outside your home. Want it somewhere else? You may face paying for the privilege.
Switch back if your bills are bigger
Disaster! You asked for a water meter but your bills got bigger. Don't worry – you can switch back to unmetered billing. Just make sure you ask your water company within the first year. It won't take the meter away, but it will change your bills back.
Beware: if you move into a house that already has a meter, you're stuck with it.
Refused a meter? Ask for assessed charges
Even if you ask for a water meter you may not get one. Your water company may say it's too difficult or too expensive, if for example you have a shared water supply or your pipework isn't suitable.
If you apply and get refused, ask if you would pay less with an "Assessed Charge".
Assessed charges are based on the average bills paid by people with meters, so check if it would be cheaper. Remember, you can only ask for an assessed charge if you applied for a meter and got turned down.
Rent your home? Ask anyway.
If your name's on the water bills, you can ask for a water meter even if you rent your home and don't own it.
Officially, you only need to ask permission from your landlord if you have a short contract (in officialeese: a fixed-term tenancy agreement of less than six months). But it's probably a good idea to ask permission anyway, however long your tenancy is.
Save water, save money with a meter
This guest post is from Faith Archer and doesn't necessarily reflect the views of the Money Advice Service. You can find out more about Faith and what she does on her blog, Much More With Less.
This article is provided by the Money Advice Service.