It shuts off a water supply so pipework or fittings can be repaired or maintained.
Main Water Shut-Off Taps for Brass and Plastic Pipe
A working stopcock matters most when a leak starts or an appliance needs changing. MacBlair stocks brass-to-brass stopcocks in 15mm, 22mm and 28mm sizes, plus poly-to-brass options for specified plastic-to-metal connections. The page lists several paired sizes, so check both sides of the existing fitting.
A stopcock should be fitted in an accessible position on the intended supply. Measure the pipe outside diameter and identify its material before choosing a replacement; the pipe fittings range includes related connections for the wider repair. Do not assume a poly-to-brass model works with every plastic pipe system.
Find and test the upstream shut-off before removing the old stopcock. For maintenance at one outlet rather than the whole property, a local valve may be more practical beside taps or a basin. The plumbing and heating section covers the other parts used when renewing supply pipework.
Stopcock FAQ's
Measure both connected pipes and check their material. The listed models include different brass and poly-to-brass sizes.
Only if the fitting is specified for that pipe type and size. Follow the pipe-system manufacturer’s instructions.
At the intended supply control point, with enough access to operate and maintain it.
Do not force a seized valve. Arrange a safe upstream shut-off and have the fitting assessed before replacement.