Either the rubber seal in the fill valve has perished (sometimes happens) and will need to be replaced - or - the valve needs to be adjusted - either lower the float further into the water or (more usually) turn the nylon adjusting screw inwards towards the valve - and do up the lock nut else it will need fixing again next week.
Good luck...
Peccavi
May 2010
howtomendit.com for free repair help, information and advice.
