Whole House Water Filter Leaking From Top (6 Step Guide)

Do you want to learn what to do when your whole house water filter leaks from the top?

A leaking whole house water filter may be the result of a faulty O-ring, or there may be a hairline crack in the threads or canister.

In this guide, I will go over...

  • Inspecting the exterior filter housing
  • Inspecting the rubber O-ring
  • Lubricating the O-ring
  • And checking the threads for damage

Let's get started with this guide!

whole house water filter leaking from top

What To Do When Your Water Filter Leaks From The Top?

Whole house water filters are great plumbing devices to keep your home's water pure and clean. However, sometimes these filters can leak from the top, which presents a potential flood hazard if it gets worse.

Hopefully the leaking whole house water filter isn't too bad yet, but there are a few steps you can take to diagnose the leak, and to prevent it from happening in the future.

Read Also: What Are The Best 10-inch Whole House Water Filter Cartridges?

1. Identify Leak On Exterior

Before you even remove the whole house water filter housing, try and determine exactly where on top the leak is coming from.

  • Does it appear to be coming from the threads?
  • Is there a small visible crack?
  • Or is the leak coming from the piping from the top?

If there is a visible crack anywhere along the housing, you are probably better off just replacing the filter housing than trying to repair it. I don't think it is a good idea to risk a flood situation to save a few bucks.

Read Also: How Does A Whole House Water Filter Work?

2. Remove Whole House Filter Housing

If you don't see an obvious crack in the whole house filter housing, it is time to remove the filter canister so you can inspect it closer.

The first step always is to turn off the water at the main water shutoff. After you have shutoff the water, you can press the pressure release button on the top of the whole house filter if you have one.

And then I recommend you open a faucet and drain most of the water out of the piping. This way when you remove the whole house water filter you won't have to deal with a lot of water getting drained.

If you have an 'outlet' shutoff valve, which is on the supply side of the whole house water filter, turn this valve off as well after draining.

And before you remove the housing, it is a good idea to place a bucket underneath the filter to catch any water.

If you have a 'big blue' type of whole house water filter, there are special wrenches that will remove the filter canister. Use this wrench to loosen the canister, and be careful to catch any draining water into a bucket.

Read Also: What Are The Best Whole House Water Filter And Softener Combos?

3. Inspect Rubber O-Ring

Once you have removed the canister, carefully remove the O-ring to inspect it for damage and which may be the source of the leak. You can pry out the O-ring with a screwdriver, or even just tap the canister upside down and it may fall out.

Clean the O-ring, and inspect if for nicks or damage. Is the O-ring still flexible and intact? If there is any damage to the O-ring, it should be replaced.

And before re-installing the O-ring, it should be coated with a silicone lubricant in order to give it a good seal. Also make sure to clean the O-ring recess on the canister if it is dirty or has any debris.

Read Also: What Are The Best Whole House Water Filters To Remove Fluoride And Chlorine?

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4. Inspect The Housing Interior & Threads

After inspecting the O-ring, I recommend that homeowners inspect the interior of the housing and the threads. If you have a flashlight, it will be helpful to notice hidden defects.

You may want to clean the interior of the canister and threads first so you can clearly see any hairline cracks. And don't forget to inspect the threads not just on the housing, but where the housing is screwed into or the top of the filter. If you notice any cracking or damage on the housing or the threads, I highly recommend replacing the entire filter housing than trying to repair it.

Read Also: What Are The Best Overall Whole House Water Filters?

5. Re-Install The Whole House Filter Housing

If you didn't find any visible defects or cracking, then the leaking may just be a result of a poorly sealed O-ring, or the canister wasn't tight enough.

After re-inserting the filter into the housing, make sure that the filter is seated properly on the bottom (the nipple should fit inside the bottom of the filter). And use the filter wrench to tighten the canister back onto the system.

6. Turn On Water & Inspect For Leaks

After tightening the housing, slowly turn on the main water.

If your whole house system has a pressure release button, press it. 

And if you have an outlet shutoff valve (supply side), turn it open. I emphasize opening the water slowly because if you turn on the main water too fast, it can cause a leak by itself.

Carefully inspect the top of the filter with a flashlight. Hopefully lubing up the O-ring, and re-tightening the canister has solved the leak.

Read Also: What Are The Best Iron Filters For Well Water?

How To Prevent Future Leaks Of Whole House Water Filters?

#1. Lube O-Ring 2-3 Times A Year

I recommend that you clean and lube the rubber O-ring every time you change the filter on your system, it should really be a part of regular maintenance.

The O-ring is a common weak area of these systems and if they aren't regularly maintained can cause leaking.

#2. Insulation For Outdoor Filters

If your whole house water filter is outdoors, I recommend covering it with insulation or some type of reflective material.

Ultraviolet light from the sun can cause degradation to the filter housing and can eventually lead to cracking and leaks.

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