Why Is My Toilet Leaking at the Base and How to Fix It? - Bens Plumbing (2024)

What are the Common Causes of a Toilet Leaking at the Base?

Over the years, I’ve seen my fair share of toilet leaks, and they often boil down to a few usual suspects.
1. First off, a faulty wax seal is the most common culprit. That wax ring sitting between the fixture and the floor is meant to create a watertight seal. But over time, that seal can degrade or get disrupted, especially if the unit has been jostled or the floor has settled.
2. Another potential cause is loose or worn-out bolts. These bolts secure your fixture to the floor, and if they’re not tight enough—or if they’re corroded—they can allow water to escape. And let’s not forget about the possibility of a cracked base. While this isn’t as common, I’ve seen it happen when someone tried to overtighten those bolts or dropped something heavy on the porcelain.
3. In one memorable case, a homeowner in Bellevue called me out to check on a recurring leak. He’d tried to fix a tolet bowl leak it himself several times, replacing the wax ring and tightening the bolts, but the problem kept coming back. Turned out, the flange—the fitting that connects the unit to the floor drain—was slightly warped, causing the wax seal to break each time he reinstalled the toilet. A simple fix with the right tools, but a nightmare without the know-how.

How to Check for a Faulty Wax Seal

Now, if you suspect a faulty wax seal, there’s a straightforward way to check.

• First, shut off the water supply to your fixture and flush it a couple of times to empty the tank.
• Then, remove the toilet and inspect the wax ring. If it’s flattened or uneven, it’s time for a replacement.

But here’s a word of caution—this process isn’t as easy as it sounds. Toilets are heavy and awkward to lift, and if you’re not careful, you could crack the base or the floor tiles. Plus, if the wax ring isn’t seated properly when you reinstall it, you’ll end up with the same leak, if not worse.

What Damage Can Occur if a Leaking Toilet Base is Not Fixed Promptly?

You might think a little water on the floor isn’t a big deal, but the truth is, a leaking toilet bowl base can cause significant damage if left unchecked. That water can seep into the subfloor, leading to rot, mold growth, and even structural damage. In Washington, where we already deal with high humidity and frequent rain, the risk of mold and mildew is particularly high.

I’ve seen bathrooms where a small leak was ignored for months, only to find the entire subfloor was rotted through. In one instance in Kirkland, what started as a simple wax ring replacement turned into a full bathroom remodel because the water damage was so extensive. The cost of repairing that kind of damage far outweighs the expense of fixing the leak promptly.

Is it Recommended to Remove My Toilet All By Myself?

Let’s get one thing straight: I’m not saying you can’t remove it yourself. But just because you can doesn’t mean you should. Removing a fixture involves more than just muscle—you need to understand how to properly disconnect the water supply, lift it without damage, and, perhaps most importantly, ensure that the new wax ring or seal is installed correctly.

Professional Ways to Fix a Leaking Toilet

So, what does a professional do differently? First off, we have the right tools and experience to assess the situation correctly. Whether it’s a wax ring replacement, tightening bolts, or dealing with a warped flange, we know how to fix a leaking toilet without causing additional damage.

We also inspect the surrounding area for any signs of water damage, something that can be easily missed by the untrained eye. If there’s any doubt about the integrity of the subfloor or the flange, we’ll address it before re-installing the unit. This ensures that the repair is not only effective but long-lasting.

If you aren’t ready to run the risk of DIY, Ben’s Plumbing has been proudly serving the Greater Seattle area for over 25 years, and in that time, we’ve earned a reputation for getting the job done right the first time. Unlike some companies, we don’t pay our service technicians on commission, so you can trust that you won’t be oversold on unnecessary repairs. Our focus is on solving your plumbing issues efficiently and effectively.

My advice? Don’t wait until a small leak turns into a major headache. While it’s tempting to try and fix these problems yourself, some issues—like a leaking toilet—are best left to professionals. If you’re in the Greater Seattle or Eastside area and need help with a toilet leak, give us a call. With our experience, the right tools, and a commitment to quality, we’ll have your bathroom back in working order before you know it.