Toilet Water Rises Then Slowly Drains? 4 Easy Fixes

Flushed your toilet only to see the water rise before slowly draining? Don’t panic! This common issue is usually caused by a clog, a blocked vent, or a problem with your drain line.

The good news is that you can often fix it yourself without calling a plumber. In this guide, we’ll walk you through the possible causes and simple solutions to get your toilet flushing smoothly again.

How Your Toilet Works (Basic Overview)

Ever wondered what happens behind the scenes when you flush? Understanding how your toilet works can help you diagnose and fix problems faster.

The Basic Components:

• Tank: Stores water until you flush.
• Flapper: Lifts to release water into the bowl when you press the handle.
• Fill Valve: Acts as the toilet’s faucet, refilling the tank after each flush.
• Float: A water level sensor that signals the fill valve to stop when the tank is full.
• Rim Jets: Small holes under the rim that shoot water into the bowl, creating a swirling flush.
• Weir: A curved pathway at the bottom of the bowl that retains enough water while allowing waste to flow past when flushed.

Now that you understand your toilet’s mechanics, let’s explore why it might be flushing slowly.

Common Causes of a Slow Draining Toilet

There are several reasons that can make your toilet drain or flush slowly. Here are some of the reasons why it happens:

1. Partial Clog in the Toilet Trap

Sometimes, even a small blockage can throw your toilet off balance. When a clog forms from too much toilet paper, non-flushable items, or even mineral deposits, water has a hard time flowing freely.

When that happens, the bowl fills all the way to the top before the water slowly drains out. Even when the blockage isn’t complete, it still stops water from moving as quickly as it should.

2. Mineral Buildup in Rim Jets

If you live in an area with hard water, then you might have seen white or sometimes brownish stains in your sink. Well, the same minerals causing those stains can also cause build up in your toilet’s rim jets – those small holes under the rim that shoot water into your bowl.

Over time, these minerals can narrow or even block these jets, kind of like clogged shower heads. When this happens, your toilet loses that strong, swirling flush that keeps everything moving smoothly. The result? A weak flush that leaves you wondering if everything will go down.

3. Faulty Internal Components

• Worn Flapper: A worn or improperly sealing flapper can reduce flushing power.
• Malfunctioning Fill Valve or Float: Incorrect water level due to a misadjusted or malfunctioning float or fill valve.

4. Vent Pipe Obstruction

If your toilet flushes slowly, one possible reason is a venting problem. The toilet system in your home has overhead vent pipes that allow air to come in and balance pressure. These vents help waste and water flow smoothly through the drain.

So, if the vent pipe is clogged (by debris, leaves, or even bird nests), air can’t flow properly. This creates a vacuum effect, making it harder for the toilet to flush efficiently. And, without proper venting, wastewater moves slowly, leading to weak or incomplete flushing.

A blocked vent can cause strange gurgling sounds from the toilet when you flush or use other plumbing fixtures.

How To Fix a Slow Draining Toilet

1. Clearing Partial Clogs

Start with a plunger:

1. Make sure there’s enough water in the bowl to cover the rubber part of the plunger
2. Position your plunger directly over the hole at the bottom of the bowl
3. Create a tight seal by pressing down firmly
4. Push down and pull up steadily, with even pressure about 5-6 times
5. Finish with a sharp pull upward to break the seal – this often dislodges the clog

If plunging doesn’t work, try a toilet auger also called a drain snake:

1. Insert the curved end into the toilet bowl drain
2. Turn the handle clockwise while pushing it down until you feel resistance
3. Continue turning to break through or hook onto the blockage
4. Slowly pull the auger back out, which should bring the clog with it
5. Flush to test if water flows freely now

2. Cleaning Mineral Buildup

If mineral deposits are clogging your rim jets, here’s how to clean them:

1. Get a small mirror and a flashlight to inspect under the rim—look for white or brownish buildup around the small holes
2. Turn off the water supply to your toilet (the valve is usually located behind or near the toilet)
3. Pour about a cup of white vinegar or a commercial mineral remover into the overflow tube in your tank
4. Let it sit for at least 30 minutes (or overnight for stubborn buildup)
5. Use a small screwdriver, wire coat hanger, or toothpick to gently clear any visible deposits from the rim jets
6. Turn the water back on and flush several times to clear out loosened minerals

3. Adjusting Internal Components

Replacing a faulty flapper:

1. Turn off the water supply and flush to empty the tank
2. Disconnect the chain from the flush lever
3. Remove the old flapper by unclipping it from the overflow tube
4. Take it to the hardware store to find an exact match
5. Attach the new flapper in the same position
6. Reconnect the chain, leaving a bit of slack (about 1/2 inch)
7. Turn the water back on and test flush

Adjusting the float and water level:

1. Remove the tank lid and look inside while flushing
2. The water level should stop about 1 inch below the top of the overflow tube
3. For cup-style floats: squeeze the clip on the adjustment rod and slide it up to raise the water level or down to lower it
4. For ball-style floats: turn the adjustment screw clockwise to lower the water level or counterclockwise to raise it
5. Flush and check the new water level, making small adjustments until it’s right

Get a new Float and Flapper here.

4. Addressing Venting Issues

Venting problems are trickier to fix but here are some steps you can take:

1. Check the vent pipe on your roof for visible blockages like leaves, sticks, or even animal nests
2. If you’re comfortable going on your roof, use a flashlight to look down the vent pipe for obstructions
3. Try running a garden hose down the vent pipe to clear minor blockages
4. For more serious venting issues, calling a professional is often the safest and most effective solution

Preventative Maintenance Tips

To avoid slow-draining toilets in the future, follow these simple maintenance tips:

• Watch What You Flush: Avoid flushing non-flushable items like wipes, paper towels, and hygiene products.
• Use Less Toilet Paper: Excess toilet paper can lead to clogs, so use only what’s necessary.
• Clean Rim Jets Regularly: Prevent mineral buildup by pouring white vinegar into the overflow tube monthly.
• Check and Replace Worn Components: Periodically inspect the flapper, fill valve, and float to ensure they function properly.
• Maintain Your Drain Lines: Use a drain cleaner or hot water flush occasionally to keep pipes clear.
• Keep Vent Pipes Clear: Check for and remove debris from vent pipes to ensure proper airflow.

Final Thoughts

By now, you should have a clear understanding of how your toilet works, why it might flush slowly, and the steps you can take to fix it. With the right tools and approach, most slow-draining toilet issues can be resolved without professional help.

However, if you’ve tried everything and the problem persists, don’t hesitate to call in a plumber to prevent further damage. A well-functioning toilet is essential, so act quickly to keep yours running smoothly!

Toilet Bowl Water Level Drops Overnight: 6 Easy Fixes

Paul Wilson( Licensed Plumber )

Paul Wilson is a highly skilled plumber with over ten years of experience in the industry. He holds an IDPH license and takes pride in his ability to tackle many plumbing issues and successfully complete even the most challenging projects.