If you’ve got a toilet that won’t stop running, you want to get it fixed asap. Not only is the constant trickle of water annoying, but it can also be costly as well. The longer you leave it, the worse the problem will get and the higher your water bill will be.
Regardless of the type of toilet, the same issues can occur. Scale can affect moving parts and get under seals, and faulty or worn parts can stop a toilet from working as intended. Thankfully, parts are inexpensive, and it's a task you can tackle yourself with a few basic tools.
Common causes of a running toilet
There are typically a few common reasons that your toilet has slow constant running water going into the bowl. Alex Woods, bathroom expert at Victorian Plumbing says, “A faulty or misaligned float valve, preventing the cistern from shutting off properly is one”.
He adds, “A worn or damaged flush valve can cause water to leak continuously into the bowl.” Other reasons he suggests, “Can be debris blocking the flush valve seat, a broken fill valve, or an improperly adjusted chain connecting the flush lever to the flush valve.”
Another reason could be that the float on the fill valve is set higher than the top of the overflow pipe. If this is the case, water will enter the overflow pipe and run into the bowl.
Alex is a marketing manager at Victorian Plumbing, a major online bathroom and kitchen retailer based in Merseyside, UK.
Identify toilet fittings
Before fixing any issues, it’s helpful to understand the names of the different parts. Here, we look at the typical components you’ll find inside a modern toilet cistern. Typically, you’ll find two plastic fittings inside. The main unit is typically located in the middle of the cistern. This is known as a flush valve unit. A thinner fitting will sit either to the left or right of the flush valve. This is known as the inlet or fill valve.
The fill valve will be connected to the water supply and will allow water to enter after flushing to fill the cistern. The flush valve releases the water into the bowl when the flush button is pressed. Attached to the flush valve is an overflow pipe to prevent the water level from rising too high.
Try these tools to help fix a running toilet
A set of chrome vanadium steel plumber pliers that consists of 250mm and 300mm models. Ideal for pipework up to 50mm.
If you need to cut any pipework these hacksaws are ideal for plastic and metal. The mini hacksaw is a good choice for those harder to reach areas.
Every DIYer should have a basic set of flathead and Phillips screwdrivers to tackle most DIY tasks including basic plumbing jobs.
How to fix a running toilet
1. Remove the lid and identify the problem
The first step is to identify the issue you have. Plumbing expert Jamie Heath, from Build & Plumb, explains the process, “Start by turning off your water supply, this can be done by locating the shut-off valve usually situated on the floor or wall behind the toilet and turning it clockwise.”
Once the water supply has been isolated, the next step is to remove the toilet tank lid and set it aside, as Heath explains: “Next, remove the toilet tank lid and place it to the side.”
Next, check the various components. “Typically, the most common cause of a running toilet is a faulty flush valve seal or flapper, caused by wear and tear.” He adds, “Identify these components and check for any visible damage. If there is damage to either one of these components, they will need to be replaced as soon as possible.”
2. Replacing a flush valve
If a flash valve seal is the problem, it likely indicates that the flush valve is old and needs to be replaced. Heath explains what you need to do: “Unscrew the flush valve from the toilet tank and remove it. Then, install the new flush valve in accordance with the manufacturer's instructions.”
This is relatively simple, and a flush valve unit is inexpensive. Alternatively, you can just remove the flash valve unit and replace the seal. These sit at the bottom of the unit and are easy to replace.
3. Replace flapper
A flapper is a seal at the bottom of a toilet tank. It controls the flow of water into the bowl. If it is leaking, you need to replace it with a new flapper, like this Fluidmaster Plastic Red Flapper from B&Q.
Health explains how, “Start by disconnecting the chain from the overflow pipe and lever, then remove the flapper. You can then install the new flapper by reconnecting it to the overflow pipe and lever.”
4. Fixing high water levels
If your toilet is still running after replacing the flush valve seal and flapper, there is another issue. Heath says, “Another common cause of a running toilet is an excessively high water level in the toilet tank and a problem with your fill valve.” This is commonly caused by water spilling into the overflow tube.
Heath reveals why, “It may indicate that the float mechanism is set too high and needs adjusting.” He adds, “Typically, in the UK, most toilets have a float cup mechanism. To adjust this, turn the adjustment screw clockwise and slide the float cup down the rod. Aim for your float cup to sit about an inch below the overflow pipe.”
5. Give the valve a clean
Another common issue is a buildup of dirt and scale that prevents the fill valve from shutting off properly. Heath suggests, “Cleaning the fill valve will remove this accumulation of dirt and debris, preventing the toilet from constantly refilling and flowing into the overflow tube”.
FAQs
Is it easy to replace a flush valve unit?
Installing a new flush valve unit like this Adjustable Toilet Dual Flush Valve from B&Q is one cost-effective way to fix a running toilet, and it’s not too difficult as Woods shares, “Replacing a flush valve unit is fairly easy. It requires only a few tools and basic DIY knowledge.” Just remember to isolate the water supply and drain the cistern by flushing before removing.
Flush valve units aren’t universal; however, most toilets use 50mm (2-inch) units. If unsure, remove and measure your old flush valve unit at the base, where it connects to the cistern drain hole. Alternatively, take it to your local hardware store or plumber’s merchant and get a like-for-like replacement. Also, ensure the unit height is suitable for your toilet cistern.
Can a running toilet increase water bills?
The simple answer is yes. Woods says, “A running toilet can increase water bills due to the continuous flow of water into the bowl. Even small leaks can waste a significant amount of water over time.”
A constant small trickle can indicate that up to 200 litres pass through a toilet every 24 hours. Annually, these can increase bills by £150 or more.
If you're fixing a running toilet it could be a good time to about fitting a new toilet seat and find out how much does it cost to flush a toilet. If you can't fix your toilet find out much you'll need to budget for new toilet costs.
