Water Meters: Reading, Bills and Leaks

Do you have to have a water meter?

Yes: in the Portsmouth Water area a meter is no longer optional. The company's moving to metering page answers the question with a single word, "Yes", and its general FAQs add that if you move into a home that already has a meter, you cannot have it taken out.

The first year comes with a cushion, the Lowest Bill Promise. For the first 12 months with a meter, Portsmouth Water says it will automatically charge whichever is lower: the bill with the meter or the bill you would have paid without one. After that year, you pay for what the meter records. Metered bills come every six months.

Portsmouth Water names Portsmouth, Gosport, Fareham and Havant among the towns it supplies, so the same metering rules reach well beyond the city. Sewerage is a separate service from a separate company (Southern Water in this area), which is why the bill has two parts.

How do you read a water meter?

You read the black digits only. Portsmouth Water's metering page says the black numbers record consumption in cubic metres and the red figures should be ignored. One cubic metre is 1,000 litres, so a reading that rises from 0412 to 0419 over a week means 7,000 litres went through the meter.

Write down the black digits and the date, then do the same a week or a month later. The difference is what you used in that period. Comparing that with the figures on your last bill shows whether the company's reading and yours roughly agree.

Readings only mean something if nothing interferes with the meter. Regulation 3 of the 1999 water fittings rules says no fitting may be installed or used in a way that causes or is likely to cause "the erroneous measurement of water". A bypass round the meter, or a branch taken off before it, falls foul of that rule.

Where is the meter usually fitted?

Most meters sit outside, in a box with the stop tap, usually in the pavement or the property's driveway, as Portsmouth Water describes it. Look for a small cast cover at or near the front boundary.

That box also marks a line of ownership. Ofwat's supply pipe guidance says the communication pipe runs from the main to the boundary, and where a company stop tap is fitted it normally marks the end of the company's pipework. From there to the first fitting or stop tap inside the house is the supply pipe, and that is yours to maintain, including "leak detection, repairs and replacement".

Inside, the house stop tap is usually under the kitchen sink. Knowing where both are saves time if a pipe ever bursts; burst and frozen pipes covers what to do first.

How is sewerage billed on a meter?

On a meter, the sewerage bill is normally worked out from 92.5% of the recorded water. Portsmouth Water passes the readings to the wastewater company, which, in the company's words, will "normally base their charges for wastewater on 92.5% of the consumption recorded by the meter".

So every cubic metre through the meter costs you twice: once for supply and, on 92.5% of it, once for sewerage. That makes leaks and wasteful fittings more expensive on a meter than on an unmetered bill.

Treatment kit can add to the bill too. The Drinking Water Inspectorate says a reverse osmosis unit produces a waste stream of 20–30% of the incoming flow and, on a metered supply, can increase bills by up to one third. The reverse osmosis page covers that trade-off, and water softeners also use water to regenerate.

Can a meter show a hidden leak?

Yes: Portsmouth Water says that if you have a meter, "that is often the best place to start" when looking for a hidden leak. Its Find it. Fix it. campaign adds that around 38% of leaks happen on customers' pipes and plumbing, not on the company's mains.

Chalk & Cistern does not print a step-by-step meter test, because no written procedure from Portsmouth Water could be opened; the company points to its own video on that page. The general idea is simple enough: a meter that keeps counting while every tap and appliance in the house is off suggests water is going somewhere.

If the leak turns out to be on the underground supply pipe, money is available. Portsmouth Water's leaks, pressure and pipes page lists:

• £100 towards a repair, or £200 towards replacing the whole supply pipe, if the work is done within 30 days of the leak being found (not for business, council or housing association premises);
• a leak allowance on metered bills when the supply-pipe leak is repaired within 60 days, limited to one allowance per property in five years;
• an allowance that covers at most the previous 12 months or two measured bills, whichever is longer, for external supply-pipe leaks only.

Tell Portsmouth Water before the repair starts; its page says that is a condition of the allowance, and every allowance is at the company's discretion. The water leaks page explains who owns which pipe in more detail.

Metered water by the numbers

• 92.5%of metered water normally used to bill seweragePortsmouth Water
• 12 monthsLowest Bill Promise after a meter is fittedPortsmouth Water
• 38%of leaks on customers' pipes and plumbingPortsmouth Water
• 60 daysto repair a supply-pipe leak for a leak allowancePortsmouth Water

Does a meter change what fittings you can add?

Not directly, but several fittings that use a lot of water need advance notice to Portsmouth Water. Under regulation 5 of the Water Fittings Regulations that includes a bath of more than 230 litres, a pump drawing more than 12 litres a minute, a reverse osmosis unit and a water treatment unit that uses water for regeneration. The water regulations page lists the rest. On a meter, those same fittings show up on the bill.

Further questions

More on pipes and bills

• Who is responsible for a water leakLeaks, pipes and rules
• Burst and frozen pipesLeaks, pipes and rules
• Water fittings rules for homesLeaks, pipes and rules
• Leaks, pipes and water rulesSection