How to replace a wall-mounted shower or bath tap

What you need

• Large adjustable spanner (32 mm opening) or 30 mm open-ended spanner
• Eccentric spanner or wide-jaw pliers with a rag
• Small 20 or 30 cm spirit level and tape measure
• Small wire brush or old toothbrush
• Bucket and rags
• Silicone gun
• Wall-mounted shower or bath tap with eccentrics, cover plates and filter washers (Grohe Start or Grohtherm 800, Tres Base or Flat, Roca L20 or Victoria-T, 40 to 250 €)
• 12 mm PTFE tape (1 to 2 €), two rolls
• Pair of 1/2 to 3/4 inch eccentrics with cover plates if the tap does not include them (6 to 12 € at Leroy Merlin or Bricodepot)
• Spare 3/4 filter washers (2 €)
• Neutral anti-mould silicone for the cover plates (Pattex Baño Sano or similar)
• Cleaning vinegar

Step by step

1. 1

   Turn off the water and release the pressure

   Shut off the mains stopcock for the flat (showers rarely have isolation valves). Open the old tap on hot and cold until no more water comes out. Put the bucket under the tap.

2. 2

   Remove the old tap

   Unscrew the shower hose. Wrap each 3/4 nut on the tap in a rag and loosen them with the adjustable spanner, turning anticlockwise. Lift the tap off. Slide the cover plates towards you and you will see the two eccentrics screwed into the wall.

3. 3

   Remove the old eccentrics and clean the threads

   Unscrew each eccentric with the eccentric spanner or the pliers and rag. If it is very stiff, do not jerk it: wet it with vinegar, wait, and apply steady force. Clean the wall thread with the brush until you see bare metal and remove all the old PTFE. Open the stopcock for a second with the bucket in front to flush out grit.

4. 4

   Prepare the new eccentrics with PTFE

   Wrap 12 to 15 turns of PTFE on the thread of each eccentric, clockwise looking at the thread head on, pulling the tape tight so the thread shows through. Slide the cover plates onto the eccentrics before screwing them in.

5. 5

   Screw in the eccentrics at 150 mm and level

   Screw each eccentric in by hand until it stops and finish with the spanner until the two outlets are 150 mm between centres, the same distance from the wall and level. Check with the tape and the spirit level. If you overshoot, unscrew it completely, fit new PTFE and repeat; never back off with the same PTFE.

6. 6

   Fit the new tap

   Stick the cover plates to the wall with a thin line of silicone along the top and sides, leaving the bottom open. Place the filter washers inside the tap nuts, offer the tap up to the eccentrics and screw both nuts on by hand alternately so they go on straight. Finish with a quarter turn with the spanner and the rag.

7. 7

   Connect the hose, open the water and check

   Screw on the hose and the shower head. Open the stopcock slowly with the tap closed and watch the two nuts and the base of the cover plates for a minute. Run the tap on cold, hot and mixed. With a thermostatic, check that at 38 degrees the water comes out warm; if it is cold or scalding, the supplies are reversed.

Which shower tap to buy: single lever, thermostatic and bath

Every wall-mounted shower and bath tap in Spain uses the same dimensions: two 1/2 inch wall supplies 150 mm apart, and 3/4 inch nuts on the tap. The eccentrics (two offset threaded elbows) correct up to 1 or 2 cm of difference if the supplies are not exactly 150 mm apart. That is why you can swap a 1980 two-handle tap for a modern thermostatic one without touching the wall.

A single-lever shower mixer (Grohe Start, Tres Base, Roca L20, or Leroy Merlin or Bricodepot own brand) costs 40 to 100 €. A thermostatic one (Grohe Grohtherm 800, Tres Flat, Roca Victoria-T) costs 90 to 250 € and holds the temperature even if someone opens a tap in the kitchen; in homes with a gas water heater or a small electric tank it is an upgrade you notice. A bath tap adds the spout and the diverter to switch from spout to shower; it is the same fitting with a wider body.

Important with thermostatics: hot water must enter on the left and cold on the right. If the supplies in your bathroom are reversed (it happens in old refits), the thermostat will not regulate. Some models have a reversible cartridge; otherwise you need a crossover adaptor, which is ugly, or the supplies need swapping with building work.

The eccentrics: where it is decided whether the tap drips or not

The eccentrics are the only tapered-thread joints in the whole job, and they are sealed with PTFE tape or hemp. Screw them in with too little PTFE and they drip behind the cover plate into the wall, and you find out months later from a damp patch in the flat below. Use too much and they do not go in far enough, leaving the tap standing off the wall.

The right amount is 12 to 15 turns of 12 mm PTFE tape wrapped in the direction of the thread (clockwise looking at the thread head on), pulled tight with your fingers. Screw the eccentric in by hand until it stops and finish with an eccentric spanner or pliers with a rag, always turning in the tightening direction; if you go past the position, do not back off: unscrew it completely, replace the PTFE and start again.

The two eccentrics must end up at the same height and 150 mm between centres. Measure with the tape and check with a small spirit level across the two outlets. That two-minute adjustment is the difference between a straight tap and a crooked one that catches your eye every time you step into the shower.

Common mistakes when replacing a shower tap

The first is tightening the tap nuts with a spanner without protecting the chrome. The jaws leave marks that never come out. Wrap the nut in a rag or use a spanner with plastic jaws. And the 3/4 nuts go hand tight plus a quarter turn: the rubber washer seals on its own.

The second is forgetting the filters. The washers in the tap nuts carry a mesh that stops grit and limescale; if you throw them away and fit plain washers, the grit goes into the thermostatic cartridge and jams it within six months. The third is not flushing before connecting: with the old tap off, open the stopcock for a moment over a bucket so the supplies spit out the grit from building work or water cuts.

The fourth, on bath taps: fitting the tap without checking that the spout sits over the bath and the shower hose reaches the riser rail. And the fifth is thinking a concealed tap is changed the same way: it is not. Concealed taps have the body inside the wall and, if it needs replacing, that is building work.

• PTFE only on the eccentrics, never on the tap nuts.
• Hot on the left, cold on the right: compulsory with a thermostatic.
• Cover plates (escutcheons) with a thin line of neutral silicone along the top and sides, left open at the bottom so any leak shows.

When to call a professional

Call us if the wall thread comes out with the old eccentrics when you unscrew them (stripped or broken supply), if the wall supplies are more than 170 mm or less than 130 mm between centres, if they are badly out of level, if the supply is iron and crumbling, if the tap is concealed, or if you want to go from bath to shower, which is a different job (see how much a bath to shower conversion costs).

Through our plumber service, replacing a shower or bath tap costs 45 to 80 € in labour, with eccentrics, PTFE and cover plates included if the new tap does not come with them. We do it in 45 to 60 minutes. We arrive in 20 to 45 minutes in Valencia, Alicante, Torrevieja and Benidorm and in 30 to 60 in Dénia, Jávea, Calpe and Altea. Fixed price on WhatsApp from a photo of the current tap, 6-month written guarantee and an invoice with IVA (VAT). More prices in how much a plumber charges.

Limescale and salt air in the shower: making the tap last

The shower is where the hard water of Alicante and Valencia shows most: limescale in the hose, in the shower head and in the thermostatic cartridge. Once a month, unscrew the shower head and leave it in warm vinegar for half an hour. Once a year, take out the thermostatic cartridge (it sits under the temperature handle, behind a large nut) and clean it with vinegar; Grohe and Tres explain it on their websites and it takes 15 minutes.

On the seafront, salt in the air attacks the chrome: dry the tap with the towel after showering and avoid cleaners with bleach or ammonia, which pit it. Choose stainless steel finishes or branded chrome; 20 € chrome loses its shine in two summers. If it is not the shower that is at fault, you have how to replace a basin tap and, for a drip without replacing anything, how to fix a dripping tap.