dripping water tank overfllow

[raypr]

I seem to have to replace the rubber washer about every 3 or 4 months to stop the overflow from dripping. Have rplaced nylon valve to no effect.
Any reason??

 

[secret squirrel]

If your changing a washer every 3/4 months then there is either something wrong with the ball valve itself, try changing the whole unit

OR

you have another problem on the system which your missing