5 Reasons Why Your Toilet Has a Weak Flush (And How to Fix It)

There are several common causes that result in a slow-flushing power toilet. These include low water levels, clogged drains, blocked drain vents, and mineral build-ups.

So, let’s go through each of them in more detail.

Reason 1: Your Water Level is Too Low

• One of the most frequent reasons for a weak flushing toilet is the water level inside the toilet tank being too low.
• If the tank doesn’t have enough water, there is a limited force that can flow into the toilet bowl. 
• The pressure in the toilet tank should be enough to push all waste into the drain.
• The Solution: You can change the water level in the tank of your toilet float, so enough water fills the tank before the fill valve is turned off.
• You might want to take a look at our in-depth guides on Six Reasons Why You Have Low Water Pressure in Your Home here!

Reason 2: Your Toilet Has a Mineral Build-Up

• When the water flows to the bowl from the toilet tank, it goes through small openings located under the toilet bowl rim. 
• Because these jet holes are pretty small, they can easily become clogged or blocked, which would result in the toilet now being able to flush properly. 
• This is a rather common scenario if you live in an area with hard water.
• The Solution: You can try a DIY solution by using distilled vinegar and a stiff bristle brush to clean the holes and break up the mineral build-up.
• You should also consider installing a water softener to keep this issue from happening again.

Reason 3: You Have a Clogged Drain

• You can typically spot a clogged toilet and use a plunger to force the blockage through the drain.
• However, a partially clogged drain can also cause weak flushing toilet issues and be more difficult to see.
• The Solution: There are a few methods you can try to unclog your toilet drain.
• If a plunger doesn’t work, consider using a drain snake or calling a professional plumber to clear the blockage.

Reason 4: There Is a Blocked Drain Vent

• Plumbing drain lines direct your toilet’s wastewater to the septic system, which is installed using vents.
• Many of these vents carry smells and hazardous gasses to the outside and can become easily obstructed. This can result in a weak flushing toilet.
• The Solution: To prevent problems with the wastewater system, you will need to use a cleaning solution to unblock the vents.
• It’s always better to hire a professional plumber to do this for you, as they might need to get to your home’s roof.

Reason 5: Your Flush Valve or Flapper is Defective

• Some problems with a slow flushing toilet have to do with the flush valve or flapper chain.
• These parts, found in the toilet’s tank, also include an overflow pipe or overflow tube and a lever. The flapper is just a rubber part shaped like a ball. 
• When you press the toilet lever in most toilets, the flush valve opening activates, and the water flow is released into the toilet bowl.
• If there is a problem with the water supply valve or any of these parts, you can easily get a slow flushing toilet.
• The Solution: Inspect the flush assembly and check if perhaps the chain is trapped or stuck.
• If the problem persists and you still get an incomplete flush, you might have to replace the flush valve entirely.