Find the source
- Drip from a bolt under the cistern — bolt washer.
- Drip from the middle under the cistern when you flush — doughnut.
- Drip from the back of the pan — pan connector (different guide).
Where the washers go (the most common mistake)
The bolt passes through a hole in the bottom of the cistern. Water sits inside the cistern, on top of that hole. So the rubber washer must go inside the cistern, under the bolt head, pressed onto the cistern by tightening the nut below. A washer only on the outside cannot stop water entering the hole.
Pro tip: Order inside the cistern: bolt head, rubber washer, cistern. Under the cistern: then pan, metal washer, nut.
Fixing it
- Turn off the isolation valve, flush and sponge the cistern dry.
- Disconnect the water supply.
- Undo the bolts from below and lift the cistern off.
- Replace the doughnut on the flush valve base.
- Fit new bolts with rubber washers inside the cistern.
- Lower onto the pan and tighten evenly side to side, until firm.
- Reconnect, refill and check.
