Free a stiff or seized stopcock

Free a seized stopcock safely using penetrating oil and gentle force, then check it seals and doesn't leak.

SC-01Get set up and find the stopcockMost stopcocks live under the kitchen sink, sometimes in a cupboard or utility room. Clear the space, put a towel down, and have a torch handy if it's dark under there. Check if there's a second, external stopcock (often near the boundary, under a small cover) so you know your options if this one won't budge.

1 each · Old towel or cloth

Buy:Tooled UpB&QAmazon

1 each · Torch

Buy:Tooled UpB&QAmazon

SC-02Try turning it by hand firstGrip the handle firmly and turn clockwise to close, anticlockwise to open. Use steady, even pressure rather than a sharp jerk. If it moves even slightly, work it back and forth a little rather than forcing it straight to full open or closed.

SC-03Soak the spindle with penetrating oilIf the handle won't turn, spray penetrating oil where the spindle enters the body, just below the handle. Leave it for 15 to 30 minutes to work into the threads. Reapply once more before you try turning it again.

1 can · Penetrating oil (e.g. WD-40)

Buy:B&QAmazon

SC-04Use a spanner on the body, not the handleIf hand pressure still isn't enough, fit an adjustable spanner onto the hexagonal part of the valve body, just below the handle, and hold it steady with one hand. Use your other hand to turn the handle gently. This stops you snapping the handle off, which is a common way stopcocks get damaged.

1 each · Adjustable spanner

Buy:Tooled UpB&QAmazon

SC-05Tap it gently if it's still stuckGive the valve body a few light taps with a small hammer to shock loose any internal corrosion or limescale. Don't hit hard, and never hit the handle itself. Try turning again after each round of tapping, reapplying oil if needed.

1 each · Small hammer

Buy:Tooled UpB&QAmazon

SC-06Work it through its full rangeOnce it starts moving, turn it fully closed then fully open several times to clear out debris and loosen it properly. Wipe away any rust flakes or limescale grit as you go so it doesn't fall into the pipework.

1 each · Rag or cloth

Buy:Tooled UpB&QAmazon

SC-07Check the gland nut for dripsWhile you're turning the handle, watch the small nut just below it (the gland nut) for any weeping water. If it drips, tighten it a quarter turn with the spanner. Don't overtighten, as this can make the handle stiff again.

SC-08Test it properlyClose the stopcock fully and run a cold tap to confirm the water has actually stopped. Open it fully again and check there's no leak around the spindle or where the pipe joins the valve. Leave a dry towel underneath for ten minutes and check it's still dry.

1 each · Old towel or cloth

Buy:Tooled UpB&QAmazon

SC-09Tidy up and know when to stopWipe the area dry and dispose of any oily rags safely, away from heat sources. If the stopcock still won't move after all this, don't force it further with more strength or a longer bar. A snapped stopcock can leave you unable to stop water flooding in, so call a plumber to replace it instead.

PART OF A BIGGER PROJECT

Your first weekend in a new home: the safety checks · Fix every drip and leak in the house · Get your home ready for winter

Tooled Up links are affiliate links: if you buy after clicking, we may earn a small commission at no extra cost to you. B&Q and Amazon links are plain searches and earn us nothing.

Save this as a project

Back to all guides

Related guides