How to fix a bath mixer tap diverter? Step-by-step guide

An old bath tap is not just a testament to years gone by, but a proper workhorse that can run for decades… until something seizes up. And most often that ‘something’ is the diverter. When you can no longer take a shower in peace or the water stubbornly comes out of both outlets at once, it’s time to roll up your sleeves.

Below you’ll find a simple guide that will walk you through repairing the diverter in a bath tap — step by step and without the stress. Check how the diverter in an old-style bath tap works and what the most common symptoms of its failure are.

How does the diverter in an old-style bath tap work?

The diverter in a classic bath tap is a mechanical part that redirects the water flow: either to the spout or to the shower handset. It usually operates with a spring and seals — water pressure moves a spindle that changes the flow path. The mechanism is simple, but, as in life, it’s the simplest things that fail most often.

The most common symptoms of a faulty bath tap diverter

If your diverter is playing up, it usually makes it very clear. It stops responding to changes, sticks, or — the classic — after switching over the water still comes out of both outlets. It can also happen that the pressure at the shower handset suddenly drops, and not necessarily because of the water company.

Why doesn’t the diverter respond when you change mode?

A sticking diverter is often the result of worn seals or limescale building up inside the tap. The water goes where it likes, and you feel as if you’re switching modes only in your imagination. Sometimes a tired spring no longer has the strength to lift the mechanism. That’s a sign it’s time for intervention — ideally a DIY one.

Water still dripping despite changing the setting — what does it mean?

If, despite switching to the shower, water still drips from the spout (or vice versa), the culprit is an internal leak. The seals may be perished, deformed or simply worn out. Limescale and grit don’t help either — they can effectively block the diverter from working properly.

Pressure problems and the diverter in an old tap

In older models the diverter often works only when the water pressure is high enough. If you notice that the diverter ‘only works sometimes’, it may be a combination of worn parts and pressure that’s too low. It’s also worth checking the tap’s filter — it may have got blocked.

How to repair a bath tap diverter step by step

Before you start, turn off the water. Always! Flooding the bathroom is the last thing you need. Once the valve is shut, get to work. To repair a bath tap diverter:

1. Remove the diverter handle — it’s usually held by a small screw under a cap.
2. Remove the diverter mechanism — it may be threaded or push-fit.
3. Check the condition of the seals and the spring — if they’re worn, buy new ones (to fit your tap model; it’s best to take the old part to the shop so you can compare).
4. Clean everything thoroughly — limescale, grit and rusty deposits can effectively jam the mechanism.
5. Replace the worn components and reassemble — make sure every part sits where it should.
6. Turn the water back on and test — if the diverter operates smoothly and watertight, you can call the mission a success!

What to do if fixing the diverter doesn’t help?

Sometimes, unfortunately, the diverter is so worn that no amount of cleaning or swapping rubber washers makes any difference. In that case the best solution is to replace the entire diverter cartridge or… the whole tap. Especially if it was already in poor shape. Modern bath taps are more efficient, but also often easier to service.

How to look after your bath tap to avoid diverter failures?

The best way to prolong the life of the tap and diverter is regular descaling — both outside and inside. From time to time it’s worth unscrewing the ends, rinsing the filter and checking the seals. And it won’t hurt to flick the diverter now and then, even if you don’t use the shower — it helps prevent it from seizing up.

Fixing a bath tap diverter needn’t be costly or complicated. A bit of patience, basic tools and the will to do it are enough. And the satisfaction of a bath where the water goes exactly where it should? Priceless.