Toilets / Plumbing question

[BigDogsWang]

I have three lavs in my house. After the toliet has flushed, you can hear the cistern refilling. Sometimes, before the mains stops re-filing the cistern, water starts to pour into the toilet again and continues to run for about 15 seconds. This happens on all three toilets. I have lifted the cistern lid, and manually lifted the ball ****, but the water stil gushes in. Is this because my mains pressure is too high, or are all my valves kerput? Please help as it's wasting soooo much water.

[gasman]

The washer in the valves may be worn away and need replacing. Easy job and the washer's cost pennies. Just isolate the loo or turn off the water then split the vale at the big nut inside the system. Fit new washer , Put valve back together again And test.

[BigDogsWang]

The thing is it doesn't do it everytime. Also, the house is only 4 years old, so would they have worn already?

[gasman]

Unusual for them all to have worn in only four years but still quite possible, i suspect the water pressure could be high especialy late evening & through the night when there is less of demand for water. For what it costs to replace them; i would try it first before fitting an expensirve PRV. (Pressure Reducing Valve) into your mains fed water.