What should I do if my internal stop tap is leaking or broken?

Your internal stop tap, sometimes called a stopcock, is the valve that controls the flow of water into your home. If it starts leaking or no longer shuts the water off properly, it’s important to deal with the problem quickly to prevent damage and to make sure you can still isolate your supply in an emergency.

Leaks can happen for different reasons. Water around the joints is usually caused by loose or worn nuts and seals, while water rising from the spindle often points to an issue with the gland nut. If the stop tap turns but fails to stop the flow of water, this usually means the washer or internal mechanism needs replacing.

If you’re confident with basic tools, you may try simple fixes. Always isolate the water first and drain your pipes by opening a cold tap.

• Gently tighten a weeping compression nut a quarter-turn while holding the tap body steady. If it still weeps, undo the nut, wrap PTFE tape around the threads and refit before turning the water back on.

• If water seeps from the spindle, try a slight nip on the small gland nut. If that doesn’t stop it, lift the gland nut, add PTFE tape around the spindle and retighten.

• If the tap won’t fully shut off, the internal washer may need replacing. This involves removing the headgear assembly and is best left to an experienced DIYer or a plumber.

Know when not to DIY. For example, you should avoid forcing seized parts, working on fragile or corroded pipework or tackling communal supplies you can’t isolate. If the valve is cracked, rounded off, or beyond a minor tweak, find a WaterSafe-approved plumber and ask for plumbing advice on repair versus replacement. They can fit approved parts or replace the stop tap entirely.

After you’ve fixed or replaced anything, turn the water back on slowly, check for drips around all joints and recheck after 24 hours. As prevention, turn the valve off and on a couple of times each year to keep it free, keep the area accessible, insulate nearby pipework and make sure everyone in the household knows where both the internal and external stop taps are located.