How to install a power shower

A power shower needs one thing before anything else: a gravity-fed water system, with a cold water storage tank (usually in the loft) and a hot water cylinder. If your home has both, fitting one is a rewarding weekend project. A confident DIYer can handle the planning and the pipework, with a registered electrician making the electrical connection. If your home runs on a combi boiler, stop here and choose a mixer shower instead, because a power shower cannot legally or usefully pump water straight from the mains.

This guide walks the job in the order it should happen: check the system, gather the kit, sort the electrics, run the water supplies, fit the unit, then fill and test it properly. The sequence matters. Most ruined installs come down to two mistakes, pumping from the mains and running the pump dry, and both are avoidable if you take the stages in turn.

Check your water system first

Start under the loft hatch, not in the bathroom. A power shower, also sold as a pumped shower, is a mixer shower with a built-in pump, and that pump is designed to boost a low-pressure, tank-fed system. Look for a cold water storage tank in the loft and a hot water cylinder in the airing cupboard. If both are present, your system can take a power shower. That tank-and-cylinder arrangement is also why the power shower is such a British fixture: millions of UK homes were built with gravity-fed plumbing, and the pump is the fix for the modest pressure it delivers.

If you have a combi boiler, or an unvented cylinder fed at mains pressure, a power shower is the wrong product. UK water regulations don't allow a pump to draw directly from the mains, and a combi already delivers mains pressure, so the pump would have nothing to boost. A thermostatic mixer shower will give you a strong, steady shower on those systems without a pump in sight.

One more check while you're up there: head. Head is the vertical distance from the base of the cold tank to the shower head, and every power shower lists a minimum in its spec sheet. Integral pumps cope with far less head than an unpumped shower, but measure yours and compare it with the model you're buying before any pipework starts. Five minutes with a tape measure now prevents an awkward conversation with a half-tiled wall later.

There is also a halfway house: if you already own a mixer shower you're happy with, a separate shower pump plumbed into its feeds gives the same boost without changing the unit on the wall. This guide covers the all-in-one power shower, which keeps the pump and the controls in one box.

What you'll need

Most of this is ordinary plumbing kit, and the shower's box will include its own template and fixings.

• The power shower unit: manual or thermostatic. Thermostatic holds your set temperature if someone runs a tap elsewhere in the house, which makes it the safer pick for family bathrooms. Most are single-outlet; dual-outlet models add a handset alongside the fixed head.
• 15mm pipe and fittings: copper or push-fit plastic, plus PTFE tape for threaded joints.
• Two full-bore isolation valves: one per feed, close to the unit, so it can be serviced without draining the system. Full-bore matters because standard screwdriver-slot valves restrict flow, and flow is the whole point of the exercise.
• A cylinder flange: an Essex or Surrey type, the proper take-off for a dedicated hot feed from the cylinder.
• Tools: pipe cutter, adjustable spanners, drill with a tile bit, screwdrivers, spirit level, masking tape and a stack of old towels.

The electrical parts (a switched fused connection unit with the fuse rating the manufacturer specifies, on an RCD-protected circuit) are best left on the electrician's shopping list, which brings us to the rules.

Sort the electrics early

The pump inside a power shower runs off the mains electricity supply, and it sits in a wet room, so the rules are strict for a reason. In England and Wales, electrical work in a bathroom falls under Part P of the Building Regulations: it needs a registered electrician who can self-certify the work, or sign-off from building control. The rules differ slightly elsewhere in the UK, so check what applies where you live.

In practice the split is straightforward. Do the pipework yourself if you're happy working with pipe, and book the electrician to install the supply: a switched fused connection unit sited outside the bathroom's zones (or a ceiling-mounted pull-cord switch), RCD protection, and the fuse rating your model's manual specifies. Book them early, because the supply should be in place and tested before the shower goes on the wall. You'll also get a certificate for the work, which matters when you come to sell the house.

Plan the water supplies

The feeds decide how good the shower will be. A power shower should have its own dedicated 15mm hot and cold supplies, run from source to shower without serving anything else. Tee off a pipe that also feeds the basin and the pump will starve every time someone washes their hands, with the temperature swinging as it does.

Take the cold feed directly from the cold water storage tank. Take the hot feed from the cylinder through a cylinder flange (an Essex flange fits through the cylinder wall; a Surrey flange replaces the top fitting) rather than teeing into the vent pipe. The flange exists to stop the pump drawing in air with the hot water: aerated water makes a pump rattle, surge and wear out early, and it is the single most common cause of a noisy install.

Fit a full-bore isolation valve on each feed near the unit, then decide how the last stretch of pipe reaches the shower. Most units accept rear entry (pipes concealed in the wall) or bottom entry (surface-run pipe), and the template in the box shows both. Concealed looks cleaner; surface-run is far easier in a tiled, finished bathroom.

If you're replacing an existing power shower like for like, most of this section is already done for you. The feeds, valves and flange are in place, so the job shrinks to isolating the supplies, swapping the unit, then flushing and priming as below. Check the new model's inlet positions and minimum head against the old one before you order, and the whole swap fits inside a morning.

Fit the shower unit

With the supplies run and the electrician booked, the fitting is the satisfying part. Position first: the spray head should sit comfortably above the tallest user, the controls should be reachable from outside the water, and the hose should reach the corners you'll want to rinse. Hold the unit against the wall, live with it for a minute, then commit.

Stick masking tape over the tile before marking through the template; it stops the drill bit skating and the glaze chipping. Drill on a slow speed, fix the backplate level, and connect the feeds to the marked inlets. Hot and cold are labelled, and reversed feeds will never mix properly. Before the final connections, open each isolation valve in turn and flush the pipe through into a bucket. Swarf, flux and sealant debris are the quickest ways to wreck a new pump, and thirty seconds with a bucket removes the risk.

Make the final connections, check each compression joint is snug rather than strangled, and clip the cover on.

Fill, prime and test

Water first, power second. A power shower pump is lubricated and cooled by the water passing through it, so running it dry, even briefly, scores the seals and shortens its life. Open both isolation valves, let the unit fill, and follow the manual's priming routine to purge the air before the switch goes anywhere near on.

Then power up at the spur and test methodically. Run the shower through its full temperature range, hold a piece of dry kitchen roll against every joint to catch weeps, and let it run hot for a few minutes before checking the joints again warm. Fit the riser rail, hose and handset, and seal around the unit only where the instructions direct, so any future leak shows itself instead of hiding behind the wall.

This final stage is also where the shower's lifespan gets decided. A pump that was flushed, filled and primed properly runs quietly for years; one that swallowed swarf or ran dry spends its life grinding towards an early replacement. Careful installation and long-term performance are not separate subjects: the first is what the second is made of.

The install at a glance

Ten steps, in order. Tick them off and the job stays on track.

1. Confirm a gravity-fed system: a cold water storage tank plus a hot water cylinder.
2. Measure the head from the tank base to the shower position and check it against the model's minimum.
3. Book a registered electrician for the fused, RCD-protected supply.
4. Run dedicated 15mm hot and cold feeds, taking the hot from a cylinder flange.
5. Fit a full-bore isolation valve on each feed.
6. Flush both pipes through into a bucket.
7. Mount the unit level and connect the marked hot and cold inlets.
8. Fill and prime the pump before switching on; never run it dry.
9. Test the full temperature range and check every joint, cold and warm.
10. Fit the riser rail and handset, then seal as the instructions direct.

Power shower installation FAQs

Can I install a power shower with a combi boiler?

No. A combi delivers water at mains pressure, and UK water regulations don't allow a pump to draw directly from the mains, so there is nothing for a power shower to do and no legal way to do it. Choose a thermostatic mixer shower instead: it uses the pressure the combi already provides and holds the temperature steady. You can compare every type across the full showers range.

Do I need an electrician to install a power shower?

For the electrical side, yes in almost every case. Bathroom electrical work is notifiable under Part P in England and Wales, and a registered electrician can self-certify it and issue the certificate. The pipework is a different matter: a confident DIYer can run the feeds and mount the unit, then have the electrician make the final connection and test it.

Do power showers use a lot of electricity?

Far less than people expect. The pump is a small motor, not a heater, so it draws a fraction of the current a 9.5kW electric shower's heating element does; that is why it runs from a fused connection unit rather than the heavy dedicated cable an electric shower needs. The real running cost is the hot water itself, because a pumped unit moves more of it from your cylinder every minute. If that bothers you, several models offer eco modes that trim the flow while keeping the pressure.

Why is my new power shower noisy or surging?

Air, almost always. If the hot feed tees into the cylinder's vent pipe instead of coming from a flange, the pump draws air in with the water, and you hear it as rattling or surging. Debris left in the pipework does similar damage, which is why flushing before connection matters. If the noise started after the pump ran without water, the seals may already be damaged, and a call to the manufacturer is the sensible next step.

Can I replace an electric shower with a power shower?

Only with new plumbing. An electric shower runs on a single cold mains feed and a high-current cable; a power shower needs tank-fed hot and cold supplies and a modest fused connection instead. That means running a new hot feed and having an electrician rework the supply, so treat it as a fresh install rather than a swap. If you're still weighing the two types, read the difference between electric and power showers.

How long does it take to fit a power shower?

Allow half a day for a like-for-like replacement where dedicated feeds already exist, and a full day or more where new feeds and a cylinder flange are needed, plus the electrician's visit for the supply and certificate. Resist rushing the priming and testing stage: the last hour of care protects the pump you've paid for.

Ready for a stronger shower? Shop power showers to compare manual and thermostatic models from Mira, Aqualisa and Triton, or read the benefits of a power shower if you're still deciding whether a pumped unit is the right upgrade.

We've been helping people upgrade their showers since 1999, with a 4.8/5 rating from more than 60,000 Trustpilot reviews, free UK delivery and 365-day returns, so you can buy the right unit with confidence.

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