If you’ve noticed water pooling around the base of your toilet or the sound of running water that just won’t stop, chances are you’re dealing with a leaking toilet tank. Fortunately, for the homeowner with some home improvement know-how, learning how to fix a leaky toilet tank is easier than you might think. With some basic tools, a step-by-step approach, and a little troubleshooting, you can stop water flooding from a running toilet before it drives up your water bill or causes damage to your bathroom floor. Homeowners can handle most repairs without calling a plumber, whether fixing leaking toilet tank bolts, replacing a worn-out tank-to-bowl gasket, or swapping an old toilet fill valve for a new one or a trusted Fluidmaster component. Use food coloring to pinpoint slow leaks, apply caulk to prevent seepage, or choose a repair kit if multiple parts have deteriorated. Be cautious not to overtighten connections, which can cause more harm than good. Whether you’re hoping to extend the life of your current toilet or deciding between a quick fix and a new toilet, this guide will walk you through the common causes and proven solutions for fixing a leaky toilet tank, right down to checking the toilet seat for stability.
What Causes a Leaking Toilet Tank?
When your toilet tank leaks, this is often the result of mineral and hard water that has compromised the rubber gaskets surrounding the spud washer and tank bolts. The spud washer connects the toilet bowl to the flush valve, while the tank bolts secure the tank to the base at the bottom of the toilet. A rubber seal between the tank and bolt head at every bolt prevents water leaks from seeping out and drips and leaks. The inside parts of the toilet, like the toilet flapper, ballcock, overflow tube, and more, may need to be addressed. We’ll look at the spud washer for leaks from the toilet bowl.
Old Gasket
A worn-out tank-to-bowl gasket is one of the most common causes of a toilet leak between the tank and bowl. This gasket can deteriorate over time due to exposure to hard water, cleaning chemicals, and natural wear and tear. If you notice water dripping or pooling at the base of your toilet, it might be time to inspect the gasket. Swapping it out with a new one is a straightforward fix and can stop the leak effectively. If you’re tackling how to fix a leaky toilet tank, replacing the old seal is a great place to start.
Unevenly Tightened Tank Bolts
If you’ve installed a new seal but the toilet still leaks, check that the bathroom and the tank are in place and must be tightened evenly on both sides to maintain a watertight seal. When one side is tighter than the other, it can tilt the tank slightly, creating gaps that allow water to seep out. Use a wrench and tighten a little at a time for best results. Having someone for best results, press down gently on the tank while you tighten, helps compress the rubber O-ring evenly. Just be careful not to overtighten, as that could crack the porcelain and lead to a much bigger issue.
Incorrect Gasket Size
Another possible issue is the size of the replacement gasket. Tank-to-bowl gaskets typically come in 2-inch or 3-inch sizes, and using the wrong size won’t create a proper seal, no matter how tight your bolts are. If you’ve installed a new gasket and the leak persists, double-check that the gasket matches your toilet model. Most repair kits specify the compatible size, so review that information before purchasing. Getting the right fit is key to stopping the leak and avoiding water flooding around your toilet.
What tools do you need to fix a toilet leak?
What supplies do you need to fix a leaky toilet tank? On top of finding new bolt gaskets and a new spud washer, you should have:
- An adjustable wrench
- Screwdriver
- Pliers
- Small wire brush
- Sponge
- Rags
- White vinegar
Steps to Fix a Leaky Toilet Tank
Once you have your tools at the ready, here is how you can go about replacing the spud washer and bolt gaskets for the toilet repair:
- Turn off the water supply by the bottom of the tank, following the water supply line from the wall and twisting the water supply valve/shutoff valve by the bottom of the toilet tank (twist clockwise).
- Empty the tank: Use the toilet flush handle, then sop up the rest of the water with the sponge.
- Secure the jaws of the wrench around the nut that’s under the tank bolt.
- Use your screwdriver to loosen and remove the tank bolt (inside the tank). Continue to use the wrench outside the tank and the screwdriver within to take out the next bolt.
- Dislocate the tank from the bowl and set it on its side (ideally with someone else’s help).
- Take out the spud washer, with a wrench if necessary.
- Put in the replacement spud washer, making sure it’s firmly attached to the spud nut.
- Remove the bolts and gaskets, and clean up with the wire brush. Ensure that any fragments of the old gasket are removed from the tank so the replacement gasket has a clean surface.
- Put in the new gaskets securely over the bolts.
- Put the bolts and nuts back. Put the bolts through the holes along the inner bottom tank, and attach the nuts under the tank over the bolts, using your hands to twist them firmly back in place.
- Reattach the tank to the bowl by going back and forth between tightening the nuts (with a wrench) and bolts (with a screwdriver); the bowl gaskets/flange need to be securely in place. Only keep from screwing the bolts at the base too tightly. Excessive force or sudden impact could quickly fracture the tank.
Preventative Measures for Toilet Tank Leaks
Regular Inspection Routines
To catch problems early and prevent water flooding or costly repairs, it’s smart to build a regular inspection routine into your home maintenance schedule. Take a few minutes each month to check for signs of wear or damage in the toilet tank, including cracks in the porcelain, rusted or leaking toilet tank bolts, worn washers, and deteriorated tank-to-bowl gaskets. A quick look now can help you avoid bigger issues down the road—and keep your bathroom dry and damage-free.
Maintenance Tips For Toilet Components
Keeping your toilet’s internal components in good working order is key to stopping leaks before they start. If you notice the flapper no longer seals properly or is beginning to warp, it’s time for a replacement. Likewise, if you’ve had repeat issues with leaks, a new flush assembly or a Fluidmaster water control unit might solve the problem for good. Many of these parts are available in a repair kit, which makes the job easier and ensures you’ve got everything you need. Staying ahead with preventative maintenance can extend the life of your toilet and reduce the need for emergency fixes.
Adjusting the Flapper and Fill Valve
If your toilet reservoir keeps filling or water runs nonstop, the issue might lie with your flapper or water inlet mechanism settings. The flapper needs to rest tightly against the valve seat to create a watertight seal, and the fill valve should shut off at the proper water level to prevent overflow. If either part isn’t aligned or functioning properly, leaks are likely. Most inlet valves can be adjusted by hand or with a screwdriver—follow the manufacturer’s directions. If adjustments don’t work, replacing the parts with a new fill valve or flapper might be your best bet to restore normal function.
When to Call a Professional
If you have a plumbing emergency, such as a leaking toilet, a bad wax ring at the toilet base, or leaks from the tank lid, rubber washers, or lock nuts, it may not happen at a convenient time. That’s why you can call A-1 Sewer & Septic Service Inc. at night or on the weekend to get fast service. Find out how an experienced Kansas City plumber can solve your plumbing disaster—call us today!