BallValve / Taps

Ball valves are typically sized by inlet pipe diameter — ½", ¾" and 1" BSP are the most common for domestic and light commercial tanks. The right size depends on your incoming supply pipework and the fill rate required; undersized valves can leave a tank slow to refill after heavy use. Check your existing pipework or ask us to match the valve to your tank's inlet bung size.

Brass valves are more durable, cope better with mains pressure fluctuations, and are the usual choice for potable water and higher-pressure applications. Plastic (often ABS or nylon) valves are lighter, corrosion-proof and perfectly adequate for rainwater harvesting or non-potable low-pressure setups. If the tank sees frequent use or high inlet pressure, brass is the safer long-term option.

High pressure valves are designed for mains-fed supplies, typically above 3 bar, and use a smaller orifice to control flow without hammering. Low pressure valves have a larger orifice suited to gravity-fed or header tank systems where pressure is much lower. Fitting the wrong type can cause slow filling, valve chatter, or leaking, so match the valve to your actual supply pressure.

Yes — any valve or tap fitted to a tank storing water for drinking or domestic use must be WRAS-approved to comply with the Water Supply (Water Fittings) Regulations. This ensures the materials in contact with water won't contaminate the supply or allow backflow. Non-potable applications such as irrigation don't carry this legal requirement, though WRAS parts are still fine to use.

Most float valves have an adjustable arm or a screw mechanism that raises or lowers the float, changing the point at which the valve shuts off. Bending the arm alters the level on basic types, while equilibrium and Torbeck-style valves usually have a more precise adjustable stop. Always leave adequate freeboard below the tank's overflow to avoid nuisance discharge.

Most tanks come with pre-fitted BSP-threaded bungs, commonly ½", ¾" or 1", so valves and taps need to match this thread to seal properly. If you're retrofitting a valve to an existing tank, check the bung size before ordering, and use PTFE tape or an appropriate sealant on all threaded connections. Where sizes don't match, a reducing bush can adapt a valve to a smaller or larger opening.