Welling Water Is Very Hard: Fix Dripping Taps and Scale

Yes, the hard water is very likely why your taps keep dripping in Welling. Welling sits in Thames Water’s Bexleyheath supply zone, which averaged about 359 mg/l in 2024: “very hard” on Thames’s scale and the hardest figure anywhere in our area. Scale scores the ceramic discs in modern taps and hardens the rubber washers in older ones, so they stop sealing. Turn off the isolation valve under the sink, replace the cartridge or washer, and descale the spout; for a longer-lasting answer, a softener with a separate unsoftened drinking tap is what Thames Water suggests.

How hard is Welling’s water?

Thames Water grades hardness in milligrams of calcium carbonate per litre. Anything over 300 is very hard. Here is how Welling compares with its neighbours, using Watergrade’s republished Thames zone data for 2024:

• Welling and Bexleyheath (Bexleyheath zone): about 359, very hard
• East Wickham (Plumstead zone): about 341, very hard
• Sidcup and Blackfen (Sidcup zone): about 331, very hard
• Old Bexley (Bexley zone): about 284, hard
• Bromley town (Bromley Town zone): about 280, hard

If you have moved to DA16 from somewhere softer, you will notice it in the kettle within a week. Check your exact postcode on Thames Water’s water quality page.

Why hard water makes taps drip

There are two kinds of tap in Welling homes, and scale beats both.

Older taps with rubber washers. Common in the original 1930s bathrooms that survived, and in plenty of outside taps. You turn the handle down until a rubber washer presses against a brass seat. Hard water leaves scale on the seat, and the washer hardens and cracks. The tap needs more and more force to shut, and then drips anyway.

Modern quarter-turn and mixer taps with ceramic cartridges. Two ceramic discs slide over each other. Scale gets between them and scratches the faces. Once they are scored, water gets past even when the tap is fully off. You will also notice the handle getting stiff.

Thermostatic shower valves and mixer bars suffer the same way. They stiffen, stop holding a steady temperature, and drip from the head.

How to fix a dripping tap, step by step

1. Find the isolation valve on the pipe under the sink or basin, a small valve with a slot or a little lever. Turn the slot or lever across the pipe to shut it.
2. Open the tap to check the water has stopped and to drain what is left.
3. Put the plug in so nothing small goes down the drain.
4. Prise off the decorative cap on the handle and undo the screw underneath.
5. Lift off the handle and unscrew the headgear or cartridge with a spanner, holding the tap body steady.
6. Take the old washer or cartridge to a plumbers’ merchant to get an exact match.
7. Fit the new part, reassemble the tap, and open the isolation valve slowly.
8. Unscrew and soak the aerator on the spout in descaler or vinegar while you are at it.

If there is no isolation valve, you will need to turn off the main stopcock. In a Welling semi it is usually under the kitchen sink or under the floorboards just inside the front door.

When it is not the tap

• Water dripping from under the tap body or round the base is a leaking connection or a failed O-ring, not the washer.
• Water under the sink may be the flexible tap tails. Check for a swollen or rusty braided hose.
• A drip from a mixer spout only on hot points at the hot side cartridge.
• Taps that spit and splutter may have air in the system, or scale breaking off inside.

Make the fix last longer

In water this hard, a new washer will scale up again. Some things slow it right down:

• descale aerators and shower heads every couple of months;
• wipe taps dry after use in hard-water areas, which stops scale building on the outside;
• do not overtighten taps, which wears washers faster;
• fit good-quality cartridges rather than the cheapest match;
• keep your hot water stored at about 60 degrees, as Thames Water advises.

Is a softener worth it in Welling?

At 359 mg/l, it is easier to justify here than almost anywhere else nearby. A whole-house softener protects every tap, valve, shower and appliance, and the immersion heater or cylinder too. Thames Water’s advice is to keep a separate unsoftened tap for drinking, usually at the kitchen sink. Our guide to whether a softener is worth it in Swanley goes through the options and the cheaper alternatives in more detail.

Hard water and your cylinder

A dripping tap is the visible sign. The less visible one is scale in your hot water cylinder and on the immersion element. If your hot water is slower to heat than it used to be, or the immersion makes a kettling noise, see immersion heater repairs in Welling.

Why bother with a drip?

On a water meter, a dripping tap is paid for by the litre, day and night. A dripping hot tap wastes heated water as well. And a drip that runs for months leaves a scale trail and stains in the basin that are hard to shift.

When to call

Call us if you cannot get the tap apart, the isolation valve will not turn, water is leaking under the sink, or the tap body itself is damaged. We fix leaking taps in Welling. More on the area is on our Welling area page.

Need a plumber now?

Call 07868 281022 and tell us your postcode, which tap is dripping or leaking, and whether you have turned the water off. We agree the price with you before any work starts.