Toilet Not Flushing Properly? Troubleshooting Guide

Why Your Toilet Flush Has Stopped Working

Nine times out of ten, a toilet flush not working comes down to a problem inside the cistern. The cistern is the large ceramic box at the back of the toilet bowl, something most of us don’t even think about until something goes wrong. Usually, it’s because the flapper valve is worn out and not sealing, or the fill valve is on the way out, or the rim jets have slowly blocked up with limescale. Sometimes it’s just the flush button itself, those dual flush buttons we use in Australia can wear out over time, and the rod that connects them can break or become loose. There’s also the possibility of a partial blockage, something part way down the pipe disrupting the flow enough that when you flush, it doesn’t quite feel right.

Title: Toilet Not Clogged But Not Flushing Properly Upload Date: July 27, 2018 Description: Video explaining common reasons why a toilet may not be flushing properly even when it is not clogged, covering fill valve, flapper and water level issues. Video Credit: Know How Now

The Cistern — Where Most Flush Problems Actually Begin

One thing that might surprise you is this; when you’ve got a toilet not flushing properly, most of the time it’s nothing to do with the bowl. It’s the cistern. The cistern’s job is simple, it fills up with water, and then when you press the button, it releases it all at once. But when the fill valve starts to play up, there isn’t enough water filling the cistern. If the water level is too low in your cistern, you’ll get a weak flush that struggles to clear the bowl. Then there’s the horror of a toilet cistern leaking. A leaking cistern is a sneaky thing, the water leaks out slowly, often inside the cistern so it runs into the bowl in a slow, steady stream. Your water bill gradually creeps up, and every time you flush there’s a bit less water behind it. If you hear your cistern filling itself when nobody’s flushed the toilet, that’s your first clue. Check the washer at the bottom of the flush valve and the height of the overflow tube. If the cistern itself has developed a hairline crack… well, time for a new cistern.

Plumber using an adjustable wrench to tighten the internal fill valve mechanism of a toilet cistern

Simple Fixes You Can Try Before Calling a Plumber

Okay, so your toilet not flushing properly has you worried… before you fork out a $150 callout fee, here are a few things you can try for yourself. You don’t need to be ‘handy’, you just need to be prepared to lift the cistern lid and take a look. First, check the water level. There’s usually a water level line marked on the inside of the cistern – if the water level is well below that line, you’ll need to adjust the fill valve or the float. The other common cause is a faulty or misadjusted fill valve. Most new toilets have a simple screw to adjust this. Flapper or flush valve seal: If the seal is distorted, cracked or dirty, it won’t seal. It should take about five minutes to replace. Bucket test: Pour a bucket of warm water into the bowl from waist height. If it flushes, you have a minor blockage and a plunger will do the trick. If not, that’s when knowing how to fix toilet flush problems yourself reaches its limit. Clean the rim jets: They are the little holes under the rim that, over time, get blocked up. Get a small brush and some white vinegar and clean them out.

Modern white toilet with silver handle and toilet paper holder in a contemporary bathroom setting

When It Might Be Time for a New Toilet

Despite your best efforts, there are times when your toilet has simply reached the end of its life. I say this with the utmost respect, but if you have a toilet not flushing properly despite several repairs, constantly playing up, and more than 15 years old, it may be time to consider a new toilet. Toilets these days use half the amount of water of older models (4.5/3 litre dual flush compared to 11-litre single flush) so the cost of a new toilet will be recouped over time with your reduced water bills. And if you are going to the expense of replacing your toilet, it might also be a good time to consider the style. A commode p trap is ideal for most standard installations while a back to wall loo will give you a clean, modern finish with the cistern hidden from view in the wall.

Modern dark bathroom with geometric tiles, glass shower enclosure and warm ambient lighting

Upgrading Your Bathroom While You’re At It

While you’ve got the plumber coming, it might also be a good time to think about other upgrades you could make. A toilet bidet attachment, for example, is something people swear by once they’ve fitted one. And if you’re already paying for a plumber to be on site, the connection cost is minimal. You could also consider installing some new tapware or tiles around the base of the toilet, or even just a new toilet seat.

FAQs

Why does my toilet flush slowly but not clog?

This could be due to low water level in the cistern, partially blocked rim jets or a flapper valve that is not opening fully. Check the cistern water level and clean the rim jets first — those two quick fixes will rectify the problem about 80 per cent of the time.

Can a leaking cistern cause a weak flush?

Yes, this is quite a common problem. If the cistern is continually leaking into the bowl (you can usually hear a gentle overflow sound) it will never fill properly. This means each time you flush the toilet, you have less pressure. Replacing the internal seal or flush valve washer should fix the problem.

Should I repair or replace an old toilet that keeps having problems?

If your toilet is over 15-20 years old and you are calling a plumber every year or two, it would probably be best to replace. Most new dual-flush toilets use less water and have a much better flush. They’ll also come with a warranty.