Toilet hard to flush? Try the simple things first

Last Updated on September 1, 2023 by Dave Farquhar

There is a fair bit of advice out there about fixing a hard to flush toilet. Unfortunately, most of them start with the more expensive and less effective remedies first. In this blog post, I’ll walk you through troubleshooting a hard to flush toilet, starting with the cheap and easy fixes first, not last.

Fix a hard to flush toilet with vinegar

When you flush a toilet, water flows through small openings under the rim called jets. These jets can easily become fouled with mineral deposits that occur naturally in your water. And cleaning under the rim with a toilet brush and ordinary toilet cleaner doesn’t necessarily do much for the jets. That’s because the brush can only reach one side.

The most effective way to dissolve hard water deposits is with acid. It doesn’t have to be a strong acid. Household vinegar works extremely well for this. Yes, the stuff you probably already have in your pantry.

And if you are wondering, either cleaning vinegar or distilled vinegar for cooking is fine. Use whichever is more convenient for you.

The vinegar treatment

Open the toilet tank lid cover. It’s not a bad idea to just pour some vinegar into the tank, but that’s not the most efficient route to get the vinegar to the jets.

For that, you need to locate the overflow valve or tube in the tank. After you locate the overflow, pour 8 to 10 ounces, or 200 to 300 ml, of vinegar down the overflow valve or tube of the toilet.

Let the vinegar sit for a minimum of 4 hours, or better yet, overnight.

If a toilet is in really bad shape, you can buy high concentration vinegar from a hardware store that is 30% vinegar rather than the normal 5% vinegar you get at the grocery store. The higher concentration vinegar is more expensive, but it will chew through the deposits more quickly.

You will usually find that the 4-hour treatment with vinegar makes the toilet operate almost like new. Not bad for 25 cents worth of vinegar. I wonder how many of the toilets I see sitting curbside on bulk pickup day just needed 25 cents worth of vinegar to get them working again.

To keep it flushing smoothly, try to make a habit of pouring a small quantity of vinegar into the overflow when you clean the bathroom. Even if it doesn’t sit for the full 4 hours, it can be effective in dissolving small quantities of mineral deposits. This keeps you out in front of a recurring problem by cleaning the part of the toilet you can’t reach through other methods.

Clearing the drain to fix a hard to flush toilet

Sometimes a toilet flushes slowly or is hard to flush because of obstructions in the drain. If it isn’t completely blocked, the toilet will still flush. But it will be harder to flush than usual because of the restricted water flow.

To try to clear the obstruction, start with just plunging. If plunging alone doesn’t seem to help much to fix a hard to flush toilet, reach for the dish detergent. Pour a couple of ounces, or about 100 ml, of detergent into the bowl. Then heat up some water. Use a tea kettle if you have one. If not, heating up your coffee pot full of water with your coffee maker is hot enough. Once you have a pot or two of very hot water, very carefully bring it over to the toilet and pour the hot water into the toilet. The degreasing action of the detergent and the heat and pressure from the influx of hot water can help break up obstructions in your pipes and it’s much less destructive than drain cleaner.

The detergent/hot water treatment is also a good thing to repeat each time you clean the bathroom, as preventative maintenance.

To prevent this from recurring, be careful about what you flush. Toilets and the plumbing underneath them are designed to carry human waste and toilet paper. That’s it. Flushing wipes, feminine hygiene products, and other bathroom trash causes clogs in pipes that can make a toilet hard to flush. It can also cause other problems.

If you think your drain may be blocked and plunging and detergent isn’t clearing it, having a handyman snake the drain is frequently cheaper than calling in a plumber.

Replacing internals

The conventional wisdom on hard to flush toilets is to buy new valve and flapper components and replace them. But this shouldn’t be the first thing you try. Other bloggers start here because it’s an easy way to make money off affiliate links.

These parts do wear out, but it can take decades. And while the Fluidmaster valves are rather good, and typically are either a match or an upgrade from whatever came with your toilet from the factory, the flappers you get at the hardware store aren’t necessarily always as good as what you are replacing. I replaced a 20-year-old flapper valve with a new one and in less than 5 years, the new one was working worse than the one it replaced.

There is no shortage of YouTube videos that show you how to replace these parts in a toilet, even in standard-in-name-only American Standard toilets. But if the problem is clogged valves, replacing these parts won’t do much to solve your problem. So before you go and spend $30 in parts and spend your Saturday afternoon rebuilding a toilet, try the vinegar fix first. Then, if the toilet remains hard to flush, start replacing parts under the lid.

Otherwise, you can end up replacing a bunch of parts and find you still have a problem. That happened to me until I learned the vinegar trick.

Dave Farquhar

David Farquhar is a computer security professional, entrepreneur, and author. He has written professionally about computers since 1991, so he was writing about retro computers when they were still new. He has been working in IT professionally since 1994 and has specialized in vulnerability management since 2013. He holds Security+ and CISSP certifications. Today he blogs five times a week, mostly about retro computers and retro gaming covering the time period from 1975 to 2000.