Why after flushing does my toilet cistern fills up very slowly - just a trickle of water ?

Question

after flushing the cistern fills very slowly - just a trickle really - unless I turn on the cold water tap in the bath which then seems to have an effect on the toilet cistern and it fills up at the normal speed!

strange but true!

is it a blockage somewhere in the pipes or something to do with the "innards" of the cistern?

Answer 1

I'd replace the fill mechanism first, that's most likely your problem.  They're very inexpensive and easy to change.

Answer 2

Sometimes small pieces of sediment can block the valve and prevent water from flowing at a rate it is supposed to.  Some of the tank fill valves have an area you can remove to clean out any debris that may have accumulated.  Many times it's just a easy and cost efficient to replace the fill valve.  They're usually about $10 -$15 at home centers.  This occurs sometimes in the screen for the faucet.  If you unscrew the nozzle of the faucet sometime you find residue in there that blocks the proper flow of water.

Answer 3

It seems as thought you are relatively familiar with a toilet as you know the ins and outs from what I have read.  Initially I was going to say, turn the water pressure higher, however I have had the same problem.

If its not the water pressure, I doubt it is blockage in the pipes as city water is chemically treated and fed through non corrosive piping.  However my terminology is not as savy as yours.  When I had this problem it was blockage from the filter inside the cistern that governs how the water is displaced.  Depending on how old the toilet - I assume its fairly old.  It would be easiest to just replace that part, as I had fixed mine 5 times before replacing it.  But its normal flow now!