We may earn a fee if you buy via links in this post (at no extra cost to you). Read our Terms & Conditions to learn more.
If your toilet lacks the proper flushing power and you’re looking for a solution, you’ve come to the right place.
Toilets usually lack flushing power because the waste pipe, siphon jet, or rim jets are partially clogged, or the water level in the tank or bowl is too low. In those cases, clear the blockage and adjust the system to correct the water levels.
Although less common, a broken fill valve or a clogged vent system may be causing your weak flushing toilet. In those cases, you should consult with a plumber before attempting a do-it-yourself fix.
In the following sections, I dive deeper into the problems that could be causing your weak flushing toilet and explain step-by-step how to solve them so you can go back to having a normal flushing toilet.
Click the links below to jump straight to a section.
- Waste Pipe Is Clogged
- Jet Flush Hole (Siphon Jet) Is Clogged
- Rim Jets Are Clogged
- Water Level in the Tank Is Too Low
- Water Level in the Bowl Is Too Low
- Flapper Valve Has Too Much Slack
- Problems With Plumbing Vent System
- You Tried to Save Money by Displacing Water in Your Tank
- If All Else Fails, Call a Plumber!
The Most Common Causes of a Weak Flushing Toilet
The first step to fixing a weak flushing toilet is to figure out the root cause. Once you identify the reason, the solutions are usually quick and easy. Below are the most common causes of weak flushing toilets, the simple solutions to each problem, and helpful pictures and videos to get you started.
Let’s jump right into it!
The purpose of a toilet waste pipe is to carry waste and water from the toilet bowl into the drain, and out of your house. If the waste pipe is completely clogged, you’ll know right away. When you flush, the water in the bowl will have nowhere to go, and the toilet will fill up as water from the tank flows into the bowl. If the waste pipe isn’t clogged, but you notice a weak flush and slow drain, you might have a partial clog.
Whether the waste pipe is entirely or partially clogged, the steps to fix it are the same.
Start with a plunger. Plungers work by forcing water back and forth through the waste pipe, breaking up whatever debris is causing the clog. The best type of plunger to unclog a toilet has a flange extension on the end of the rubber part like this one on Amazon. The flange fits better and makes each plunge more effective. Plungers shaped like a bell without a flange extension might work on your toilet but are designed for shower drains.
Check out this video to learn the most effective plunging technique.
If plunging doesn’t do the trick, use a toilet snake. Toilet snakes are tools designed with the specific purpose of breaking up clogs that occur beyond the toilet. They have long coiled cables that you extend deep into the piping and break up or retrieve the debris, causing the clog. If you don’t have a toilet snake already, this one is one of the best selling and highest rated on Amazon.
Here’s a quick video showing you exactly how to use a toilet snake.
The jet flush hole, often referred to as the siphon jet, is a compartment in the front of the toilet that holds water and releases it at an angle to push waste directly into the trap upon each flush. Over time, calcium and other deposits can develop and block the jet flush hole, weakening your toilet flushing power.
Use an acidic toilet cleaner like Zep (view on Amazon) and a brush to clear the jet flush hole of any build-up. Find a brush small enough that you can fit in the hole and twist several times to make sure the passageway is completely clear.
Underneath the rim of your toilet are small holes called rim jets that release water from the tank into the bowl every time you flush. Similar to the jet flush hole (or siphon jet), deposits can develop around the rim jets over time, block the water flow, and weaken the flushing power. Water should flow fast and aggressively out of the rim jets on every flush. If that doesn’t happen, it’s time to clear them out.
The best way to completely clear the rim jets is to plug each jet with plumbers putty, pour acidic toilet cleaner into the overflow tube located in the toilet tank, and let the acidic cleaner sit for a while and dissolve the build-up and deposits. After a few hours, remove the plumbers putty and flush several times. Finish the job by scrubbing with a brush to remove any leftover debris.
When the water level in your toilet’s tank is too low, your toilet won’t flush properly. A low water level also increases the risk of clogging since there’s less pressure flowing through the waste pipe. Every toilet has a water level mark that indicates exactly where the water should be. The standard water level in a toilet tank is right below the overflow pipe. If the water in your tank is below that mark, that is most likely the root cause of your poor flushing toilet.
The water level in every toilet is determined by the float, which is located in the tank. When your toilet is not in use, the float sits on top of the water keeping the fill valve closed. When you flush the toilet, the water flows from the tank into the bowl, and the float drops, which opens the fill valve and allows new water to enter the tank. As the tank refills, the float rises with the water level. Once the float gets to a certain height, the fill valve closes.
To adjust the water level in the tank, you simply adjust the height of the float. Each toilet is a little different, but most have an adjustment screw that you turn with a screwdriver. To increase the amount of water in your tank, adjust the float so it’s higher and more water flows into the tank before it cuts off the water supply.
Here is a quick video showing you exactly how to adjust the float and control your tank water level.
If the water in your tank is too high, adjust the float in the opposite direction so less water is required to close the fill valve.
When the water level in your toilet bowl is too low, it won’t flush with the proper strength. If the water level in your toilet’s tank is normal, but the water level in the bowl is low, you likely have an issue with the fill valve apparatus located in the tank. If the fill value cracks and leaks water, it takes water pressure away from the tube that fills up the toilet bowl.
To figure out if you fill value is causing the water level in the bowl to be too low, remove the tank lid and flush a few times. If water is squirting out of the top of the fill valve, it has a leak. This can be somewhat difficult to diagnose yourself, so I suggest calling a plumber if the issue isn’t obvious.
The solution is simple; you have to replace the faulty fill valve apparatus with a new one. However, executing this solution can be confusing if you’ve never done it before. The best way to learn is to see it done. Check this video to see the exact steps in action.
If you have to hold down the handle for a long time to get a good flush, the flapper has too much slack. The flapper is a valve at the bottom of the tank that is attached to the flush handle by a chain and rod. When you push the handle down, the rod lifts the chain opening the flapper valve and allows the water in the tank to flush into the bowl. If the chain is too long, the flapper closes too fast and doesn’t allow enough water to flush.
Most flapper chains have a clip that you can easily latch onto a different link to shorten the slack. If yours doesn’t, cut the chain with a wire cutter. By reducing the slack on the chain, the flapper will open easily and stay open longer each time you press the handle. This adjustment allows the proper amount of water to flush into the toilet.
Most homeowners don’t realize that their plumbing, like many other systems in their home, needs a vent system to operate correctly. The plumbing vent system regulates air pressure, helps move water through the pipes, and removes gas and odors from the home.
When there’s something wrong with the plumbing vent system, it impacts water pressure, drainage, and flushing power. You can usually tell something is wrong if you hear gurgling sounds in the drains, start to notice a slow drain in the shower or sink, or smell disgusting sewage odors.
If you suspect that your toilet has a weak flush due to a vent system issue, call a plumber immediately. Vent systems are not something that you’ll be able to troubleshoot yourself, even with the help of Google and Youtube.
Your plumber will inspect the vent pipe on your roof and use specialized equipment to check for a blockage. If they find a blockage, they’ll use tools to break it up or flush it out.
Check out this video to get a look at what your plumber will do if he or she suspects a clog in the vent pipe. Again, I do not recommend trying this yourself.
If your plumber doesn’t find a blockage, they will run several other tests and inspections to identify and solve the issue.
In a recent article, I wrote about saving money on your water and sewer bill, one of my suggestions was to displace water into your toilet’s tank by placing a water bottle filled with pebbles in the tank. By doing so, your tank will refill with less water reducing the water you use for each flush. This technique certainly saves water and money, but it could negatively impact flushing power.
If you’re trying to be a savvy homeowner and save money by displacing water in your toilet’s tank, but now your toilet has a weak flush, remove whatever you’re using to displace the water or try a smaller object. If you are using a large water bottle, try a smaller one. If you try a smaller water bottle but still have a weak flushing toilet, remove it entirely and make up the savings on your water and sewer bill elsewhere (I provide over 20 suggestions in the article).
Weak flushing toilets are a common issue in homes, so if you’re having trouble, don’t panic. Go through each of the causes in this article, and if none of them do the trick, call a professional. If you don’t already have a plumber that you trust, you can get free, no-obligation quotes from plumbers in your area on HomeAdvisor.com. You can also read reviews of each plumber and submit questions so you can find one that will do a great job at a fair price.
Do you know of any other tips for dealing with a weak flush? Let us know in the comments below!
If you found this article helpful, you should also check out:
- 6 Ways to Fix Standing Water in the Bottom of Your Dishwasher
- Liquid-Plumr vs. Drano: Which Drain Cleaner Is Better?
- Green Gobbler vs. Drano: Which Drain Cleaner Is Better?
- Does Drano Work? How Does Drano Work? An In-Depth Review
- Tankless Water Heaters: 7 Pros and 6 Cons You Need to Know
- How to Fix a Dryer That’s Not Drying (10 DIY Solutions)
- How Long Do Hot Water Heaters Last? (and How to Extend Their Life)
- How Long Do Dishwashers Last on Average?
- The Ultimate Home Maintenance Checklist (Printable)
- HomeAdvisor vs. Angie’s List: Differences, Similarities, Pros, and Cons
- How to Clean Stainless Steel Appliances Without Streaking: 4 Easy Steps
- How to Fix a Cracked or Chipped Porcelain Sink (8 Easy Steps)