Is a Water Pressure Pump Worth It?

Pressure or flow: find out which you are short of

Before spending several hundred pounds, work out whether the problem is pressure (how hard the water pushes) or flow (how much arrives each minute). A pump raises pressure. If the pipe into the house can only deliver a small volume, a pump cannot manufacture more water. It just empties the pipe faster and may pull the pressure down for your neighbours.

Two quick tests. Fill a bucket from the kitchen cold tap for exactly one minute and measure it with a jug; that is your flow at the main. Then run the bath and a basin tap at the same time and watch whether the kitchen flow collapses. Strong flow that drops sharply when a second tap opens points to a small or partly blocked supply pipe, not a pressure problem. Our guide to how to increase water pressure covers those free and cheap fixes first.

Also check the obvious: the stopcock fully open, no half-shut valves, and no pressure reducing valve set too low. A surprising number of weak supplies are a stopcock that someone turned down years ago.

Which system do you have?

The kind of pump that makes sense depends entirely on where your water comes from. There are three common set-ups in London homes.

• Gravity-fed: a cold water tank in the loft feeds a hot water cylinder in an airing cupboard. The pressure at your taps depends on how high the tank sits above them, roughly 0.1 bar for every metre. A shower one floor below the loft may get only 0.2 or 0.3 bar. This is where pumps shine.
• Combi boiler: no tanks. Hot and cold both come straight from the mains through the boiler. The boiler’s performance is limited by the mains flow and pressure reaching it.
• Unvented cylinder: a sealed hot water cylinder fed directly from the mains, with no loft tank. Pressure is mains pressure, reduced by the cylinder’s own valve.

Shower pumps and gravity pumps are built for tank-fed water. Their makers state they must not be connected to a combi boiler or an unvented cylinder supply, which are already at mains pressure.

Gravity-fed homes: yes, usually worth it

If you have a loft tank and weak showers, a pump is the standard fix and usually a good one. There are two routes.

A shower pump boosts one shower. It draws from the stored hot and cold supplies and pushes both through the shower valve at higher pressure. A single-impeller pump boosts one supply, usually the blended water after a manual mixer valve; a twin-impeller pump boosts hot and cold separately before the valve and suits most mixer and thermostatic showers. Well-known makes include Stuart Turner and Salamander, and retail prices run from roughly £150 to £700 or more depending on the bar rating and whether it is a negative-head model.

A whole-house pump boosts several outlets from the tank, so every tap and shower gains pressure. It costs more and needs a larger, well-supported loft tank with enough capacity to keep up with the pump. Most twin and whole-house pumps are rated above 12 litres a minute, so they need notifying to the water company before they go in, even though they draw from the tank.

Watch for the details that decide whether a pump works well. If the shower head sits higher than the bottom of the loft tank, you need a negative-head pump or a flow switch kit. The cold tank must hold enough water to keep up with the pump, and the hot supply usually needs a proper take-off from the cylinder, often a Surrey or Essex flange, so the pump does not pull air. Pumps also make noise and need their own electrical supply from a fused spur, which a qualified electrician should install, particularly anywhere near a bathroom.

Mains and combi homes: usually not the first answer

On a mains-fed home the limits are tighter. The Water Supply (Water Fittings) Regulations 1999 require you to notify the water company before installing a pump or booster that draws more than 12 litres a minute, directly or indirectly, from a supply pipe. The water company can refuse consent or attach conditions, and if it has not replied within ten working days consent is treated as given. That limit exists because a strong pump on the main can pull the pressure down in the street and, in the worst case, draw water back from fittings.

Some products are designed for mains boosting within those limits. The Salamander HomeBoost, for example, is sold for exactly this job. Whatever the make, check its stated maximum draw against the 12 litres a minute threshold before it goes in. They can help where the pressure is modest but the flow is reasonable. They do not cure a supply that is simply too small.

The alternatives often work better. An accumulator is a sealed vessel that stores mains water under pressure, which refills from the main whenever water is not being used and releases it quickly when you need it; it can help a combi or unvented system cope with a weak supply without drawing hard on the main. Replacing an old half-inch lead or undersized supply pipe with 25mm or 32mm plastic pipe fixes the root cause, although it means digging and is a bigger job.

The honest costs

These are typical market ranges, as a guide. A shower pump runs from about £150 to £700 or more for the unit. A whole-house or multi-outlet pump costs from around £330 to well over £1,000. Mains boosters are in the £150 to £400 range for the unit. Fitting labour varies with access, the state of the tank and whether new pipework or a flange is needed, and usually adds several hundred pounds.

An accumulator installation costs more, often in the high hundreds or low thousands depending on size. A new supply pipe from the boundary to the house is the largest job, priced by length, digging and surfaces; get a survey before committing.

If a pump has already been fitted and the pressure is still poor, or it cycles on and off by itself, it may be starved of water, airlocked or have a failing flow switch. That is a service or repair job rather than a reason to buy a bigger pump. See low water pressure repair.

Typical market prices, not our price. The £60 call-out covers a visit to diagnose the cause. The repair price is agreed with you on site before any work starts.