Tap Stiff or Hard To Turn

What's happening?

A tap that turns easily when new gets stiff because something inside no longer slides. On a traditional two-handle tap the spindle turns a washer onto a seat, and limescale or corrosion on the spindle thread makes it grind. On a mixer with a single lever or a quarter-turn tap, a ceramic cartridge does the same job; the cartridge needs a quarter or half turn to go from off to full flow, and when its seals swell or it scales up it stiffens. The handle itself can also bind on a worn or over-tightened grub screw. Stiffness first, leaking later, is the normal order: the fix is cheapest before the spindle seizes.

What usually causes it?

• Limescale on the spindle or inside the cartridge in a hard water area
• A ceramic cartridge whose seals have swollen or hardened with age
• Corrosion or dried grease on the spindle thread of a two-handle tap
• An over-tightened grub screw or handle that rubs the body
• A worn gland or O-ring dragging on the spindle
• A tap not used for months, whose parts have seized

Is it dangerous?

No, but forcing a stiff tap can snap the spindle or crack the body, turning a stiff tap into a leak. If the tap will not close fully, shut the isolating valve under the sink until it is repaired.

Can I fix it myself?

Close the isolating valve, open the tap to drain it, and remove the handle by its cap and grub screw. On a quarter-turn or lever tap, unscrew the cartridge and look for scale; soak it in descaler or white vinegar and work the stem until it moves freely. A cartridge that is cracked or still tight should be replaced as a whole, matched on size, thread and number of splines to the old one. On a two-handle tap, clean the spindle thread and smear a little silicone-based tap grease. Do not use general-purpose grease or oil near the seal: some damage rubber. Refit and test under slow supply.

When should you call a plumber?

Call a plumber when the isolating valve does not hold, when the cartridge or spindle is stuck fast, when the brand uses a special cartridge you cannot match, or when a stiff tap also leaks from the handle or base.

What will the plumber actually do?

• Isolate the tap and strip it to the cartridge or spindle
• Descale and re-grease or replace the cartridge, washer or O-rings
• Match a maker-specific cartridge by size, spline count and thread
• Check the isolating valve and the flexible tails while the tap is off
• Test the tap through its full range and check for leaks at the handle

Who fixes this

• Tap and shower repair

Questions people ask

Sources & References

1. Crosswater: what to do if a tap handle is stiff or won't turn
2. WaterSafe: how to stop a dripping tap