No one wants a toilet that won’t flush. We don’t really need to tell you why, but when it does happen, you’ll want to know how to fix it, and quickly. Thankfully, it’s a job you can do yourself as long as you follow some simple steps.
In this handy DIY guide, the experts reveal the common reasons your toilet may not flush, regardless of the type of toilet you have. And once you have identified what's causing the issue, we give you the knowledge and know-how to fix it yourself.
Reasons why a toilet won't flush
If your toilet stops flushing, there can be a number of reasons, as Jamie Heath, plumbing specialist at Build & Plumb, shares: “Low water levels can be a common cause of toilet flush problems as a toilet cistern needs a full tank of water to create enough force for a sufficient flush.”
He adds, “Multiple issues can cause low levels of water in the cistern, for instance, a faulty flapper, a malfunctioning fill valve or a low float.”
However, there may be a different reason, adds Heath. “Your toilet might not be flushing due to a broken flush button or handle.” He continues, “If the connection between the button and flush valve is disjoined, this will prevent the toilet from flushing.”
Finally, it might be something simpler that a good cleaning can sort out, explains Heath: “It can also be caused by a damaged flush button due to wear and tear or a build up on dirt and grime that’s causing the button to stick.”
Jamie is a highly experienced manager with over 24 years of expertise in the Plumbing & Heating sector. He now brings his knowledge to Build & Plumb, an online retailer, supplying top-quality products for DIYers, renovators, and trade professionals alike.
Try these to help solve your toilet flush issues
A neat and compact close coupled toilet. It has a rimless design and is supplied with a wrap-over seat that has soft-close hinges.
A dual flush valve unit that is pre-fitted in a lot of toilets, check if it matches your flush unit. Has adjustable height and overflow options.
A basic close coupled toilet in white. Measures 635mm (D) x 748mm (H) x 382mm (W) making it ideal for smaller spaces.
How to fix a toilet that won’t flush
How you fix a toilet that won’t flush will obviously depend on the reason behind the problem. Here, we look at how to fix two common problems. Don’t forget to isolate the water supply when removing any parts.
You should have isolation valves (like this Pipestation 15mm Isolation Valve from Amazon). Turn the screw on the isolation valve so it is horizontal. If you don’t have an isolation valve its a good idea to get one installed.
Fix 1: Raise the fill level
“An incorrect float height can cause low water levels in your toilet’s cistern,” shares Heath. “To raise the float height, turn the adjustment screw or clip and slide the plastic float cup further up the rod.” He adds, “Typically, it’s best to place it about an inch lower than the overflow pipe.”
Heath shares another issue that might be causing the problem: “Low water levels can be a result of a problem with the fill valve, either from wear and tear or a blockage.” He adds, “To fix this, start by inspecting your fill valve and cleaning it to dislodge any dirt or debris.
Scale might be the issue. Heath offers a simple fix. “It may have a build-up of limescale on it, so if this is the case, then you can soak the components in a limescale remover.” However, if it is significantly damaged, it might be time for a new fill valve, like this VeeBath Toilet Inlet Valve Bottom Entry from Amazon.
“A faulty flapper can also be a cause of low water levels in your toilet’s cistern, resulting in a weak flush,” explains Heath. “To fix a damaged flapper valve, turn off the water supply and check the valve for cracks or obvious wear.” He adds, “If the valve is damaged, then it will need to be replaced with a new flapper valve.”
Fix 2: Clean/replace flush valve unit
If the problem is not the fill level, it is most likely the main flush valve unit causing the issue. First, isolate the water supply and flush the toilet to empty the cistern. Now twist the flush unit to remove.
Once the flush valve unit has been removed, check the bottom of the unit for debris and clean it if needed. Use a kitchen scourer to remove gunk and limescale. For hard-to-reach areas, you can use an old toothbrush. However, this might not solve the problem. If this doesn’t fix the issue, replace the unit.
Fix 3: Clean or replace the flush button/handle
A simpler issue could be a problem with the flush handle or button. Heath explains how, “Remove your cistern lid and ensure that the flush button is connected to the flushing mechanism by a rod. If the button seems disconnected, then carefully reattach it.”
He adds, “Alternatively, if the button itself is cracked or broken, then it will need to be replaced with a new flush button or handle.”
FAQs
Matthew Powell created WarmZilla in 2018, having forged a successful career as a heating engineer over many years. WarmZilla is redefining the boiler purchasing and installation process and also specialise in repairs, home cover and all aspects of domestic heating.
What's a quick fix if a toilet isn't flushing?
Matthew Powell, Owner of WarmZilla, shares a couple of quick fixes for toilet flush issues: "Fill a large bucket with at least a gallon of water and pour it quickly and forcefully into the toilet bowl. This should create enough pressure to push the waste through the drain, simulating a normal flush. This is especially useful when there’s no running water, but the toilet is still functional."
There may be a more serious issue, such as a blockage. For this, Powell says, "Try a plunger; this may help clear the obstruction." He adds, "Make sure to use a flange plunger, which is designed for toilets. Press it firmly over the drain hole and plunge up and down several times to dislodge any clog."
But if it's a stubborn blockage, Powell suggests an alternative, "If this doesn’t work, you may need to use a hard wire to break up tougher blockages. Good luck!" Or you can use a drain snake/toilet auger.
If you’ve tried these methods and your toilet still won’t flush, it might require a professional repair.
How much does a plumber charge to fix or replace a toilet?
The cost to repair/fix a toilet will depend on a number of factors as Powell shares, "The cost of repairing or replacing a toilet depends on the nature of the problem, the type of toilet, and labour costs in your area."
He says, "For minor issues like replacing a siphon, ball valve, handle, or chain, a plumber may charge between £50 and £100." He adds, "If your toilet is constantly running or not refilling properly, the cost could range from £80 to £150, depending on whether parts like the fill valve or flush mechanism need replacing."
As you might expect for more complex problems that price goes up as Powell shares, "Fixing a leaking toilet base or unclogging a severe blockage, can cost £100 to £250. These repairs often require more time and expertise, especially if the toilet needs to be removed and resealed."
If you decide its time for a new toilet Powell says , "Expect to pay between £100 and £250 for labour alone."
He finishes with some wise advice, "For accurate pricing, it’s always best to get a quote from a qualified plumber. If your toilet is frequently causing issues, replacing it with a more efficient model might be a cost-effective solution in the long run."
Fixing a toilet flush valve is a cost effective option to replacing a toilet. But it could be time to fit a new toilet. Check out our toilet dimensions and downstair toilet ideas guides to help you decide which will be best for your home. Read our new toilet cost guide to see how much you can expect to pay.
