We have mains water (combi boiler). There is currently no water upstairs, hot or cold, to anything including the loo (though the loo still has the normal level of water in it but won't flush). Downstairs is fine though. Could the loo have been blocked down in the pipe somewhere and affected all of the water upstairs?

Mrs W, August 2009

you have blocked mains supply pipe work or faulty stop taps either in the house or at the boundary, failing that you have a large burst/fractured mains supply. put a listening device(eg metal bar) up against the stop tap and to your ear, can you here running water, if so you could have a burst. Call your water authority.

Bored Plumber, August 2009

Feel free to fill the upstairs cistern with a bucket and flush that way....although you can simply pour water down the pan from the bucket to achieve the same thing.
If your boiler is showing low pressure at the gauge, this is purely to do with the sealed central heating (radiator) system - and nothing to do with your problem here. However - if your boiler pressure falls to zero, a fail safe device could prevent it (the boiler) firing up. Aim for a pressure of between 1 to 2 bar on the gauge. More than 3 bar will cause the pressure relief valve on the boiler to open which can be a real bore.
You say that the downstairs pressure seems to be lower than normal now? Therefore I must conclude that for some reason, the mains water pressure to your house is lower than it should be. This could certainly prevent water flow to the upstairs, but your central heating - if you are using it - will be unaffected. I just can't think of anything else - and I do hope you find the problem! Best wishes!

John, August 2009

BUT seems to have little pressure as well (not BACK)!

Mrs W, August 2009

Actually, thinking about it, our gas boiler has been showing low pressure recently - could it be that?

Downstairs water works back seems to have little pressure as well.

Mrs W, August 2009

Can I pour some water into the cistern (from downstairs) and then flush the loo?

Mrs W, August 2009

No, we haven't touched the stopcock at all. I will have to check with the neighbours to see if they are having problems too. Why would it only be upstairs and not downstairs?

Thanks for all of your help, John.

Mrs W, August 2009

Errr thanks for posting back...that in itself is a first! For your loo to flush, the water level in the cistern needs to be near the top - often there is a line inscribed on the ceramic. If this level is low, then the syphon mechanism can't flush the loo. The water level in the pan stays constant and has nothing to do with your situation.
So - you can't get either hot or cold water upstairs? That has to indicate a water pressure problem really - I think its very unlikely for you to have a blockage in both the hot and cold supply pipes...have you been turning the house main stopcock off recently, or have your neighbours similar problems?

John, August 2009

Normal level of water in the pan. Not sure what is normal in the cistern - water is currently about halfway up which may be a bit lower than usual going by tidemarks!

Mrs W, August 2009

Ye gods thats an odd one....your combi boiler will only provide you with hot water upstairs - it has nothing to do with the cold supply. As you have neither a hot or cold supply upstairs, I'm wondering if the water pressure to the house has failed for some reason? If the loo has the normal level of water in the cistern (not the actual toilet pan) it will flush as normal. Unless....you're winding me up...never fails!!

John, August 2009