How to diagnose your toilet leak like a proper plumber.

You've just noticed a puddle of water next to your toilet. A puddle left by the poor aim of the male members of the household maybe! You wipe it up. You pop back about an hour later and there it is again in exactly the same spot. Must be a leak you think. You rummage in the kitchen cupboard and find an old margarine tub. You place this where the water appeared. You monitor the water level in the tub over the next couple of days whilst contemplating what action to take next. It's not much of a leak after all. Not even worth calling a plumber. Can't actually tell where it's coming from.

What makes identifying a leak on a toilet difficult?

The trouble with toilets is that they have lots of curves and a nice smooth finish. Any small leak can trickle down from above, follow the contours of the pan, and leave a puddle which is no where near the actual leak itself.

I remember a few years back going out to fix a leaking toilet. It was in November and we were just having the first really cold winter weather. Customer showed me the toilet and sure enough it was pretty wet around the base of the toilet. The chap said it seemed to be worse after the toilet had been flushed and especially in the morning. I dried everything off and checked everything on the toilet. I couldn't for the life of me find where it was leaking from. To cut a long (and frustrating) story short in the end it was simply down to condensation. Due to the sudden cold snap the heating had been put up to max and the bathroom was nice and warm. However, each time the toilet was flushed, the cistern was refilling with icy cold mains water. This interaction between the warm and cold was creating heavy condensation on the outside of the cistern and this was trickling down the toilet and pooling on the floor below. Of course this was at its worst in the morning when the water was at its coldest and the heating at its highest. There are ways to reduce condensation forming on toilet cisterns but I'll leave that for a future blog. Lets concentrate on leaks.

Ask yourself some simple questions to help you figure out where the leak is from?

1. Does your toilet leak even when it's not being used?
If your toilet leaks water even when it has just been sitting there without being used (flushed that is) the most likely source of the leak is from the fill valve/ball valve. Either:

• from the union between the valve and the cistern. If there is a dribble from where the valve enters the cistern then it usually just needs the backnut tightening up. You will need to take the cistern lid off and hold the valve while you tighten the nut to ensure the valve doesn't turn as you tighten it. Take care not to overtighten as these backnuts are plastic and can split. 

valve backnut

• from the union between the valve and the incoming water supply. Again it may just need the nut tightening up. More often than not though it will need a new washer (fibre or rubber depending on union type). Just be careful you don't cross-thread when you tighten it back up (believe me this is very easy to do, and any plumber that denies ever cross threading a toilet valve is probably telling porkies!)

isolation valve with fibre washer that fits directly on to the bottom of the toilet valve

Before I go any further I should mention that before you attempt to do any repairs: 

MAKE SURE YOU ISOLATE THE WATER TO YOUR TOILET and EMPTY THE WATER FROM THE CISTERN BY FLUSHING IT (or use a syphon if it can't be flushed). Also have some rags handy to catch any drips.

2. Does your toilet only leak when you flush it?

If a pool of water only appears after you have flushed then there are a few possibilities.

• leaks from the pan connector (the plastic pipe that connects the back of your toilet to the main waste pipe). If it leaks from here it is often because the toilet pan is not properly fixed to the floor. What this means is that every time someone sits on the toilet the pan moves slightly and eventually the seal on the pan connector can work its way loose. I've seen all sorts of attempted repairs on these usually involving lots of silicone, but unfortunately most don't cure the problem (and just look a horrible mess!). Remember, this will be dirty toilet water that is leaking. The best solution is to replace the pan connector and make sure the pan is securely fixed to the floor. If you can't avoid some movement (sometimes a problem with toilets on wooden floors) then you may be best off using a flexible pan connector which will allow for this slight movement without it leaking.

pan connector

• leaks from the donut washer (yes the dreaded donut washer!). If you have a fairly new toilet and it leaks only when you flush then it could be that your donut washer is out of line. The donut washer creates a seal between the cistern and the pan. They can be a right pain in the **** because if they don't create a proper seal you will get water dripping down every time you flush. If you need to replace the donut washer (make sure you get the right size) just take extra care when lowering the cistern onto the pan that everything is lined up and the washer hasn't slipped out of place.

• If your toilet is not a close coupled one then you don't have to worry about donut washers but you may have a flush cone instead. You will find these on low-level and concealed cistern toilets and they create a seal where the flush pipe enters the pan. I find the black rubber ones (below) create a much better seal than the cheaper clear plastic ones.
  

and finally...…

what I have mentioned here are the most common toilet leaks I have come across over the years. There are always other possibilities of course. Like the toilet pan I once went to that had a hairline crack in it (believe me that took me a while to figure out!). Don't even get me started on back to wall and concealed cisterns! I must admit when it comes to toilets, keeping it simple is always best in my eyes.

Remember to also check out my other 'toilet' themed blogs:

Don't get ripped off! How much should you actually pay to get your toilet fixed? 

LEVER or BUTTON - that is the question 

If you live in Derby (or near by) and have a leaking toilet and don't fancy the challenge of fixing it yourself then get in touch. Contact me by phone or email.

Also check out my prices and special 'toilet overhaul offer' on my website.