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The Home Depot

How to Fix a Clogged Toilet

Pro Referral > Home Guides > Plumbing > How to Fix a Clogged Toilet
How to Fix a Clogged Toilet

So you are backed up, that is--your toilet’s backed up. To anyone that has lived in a house, this may seem like an easy thing to fix, and typically it is. The simple fact is that a clogged toilet is likely the most common plumbing issue you'll have to deal with as a homeowner. Grab a plunger and plunge. Right? Right.


It probably goes without saying that the best way to unclog a toilet is to not let it get clogged in the first place. Easier said than done, especially if you live in a household with children. Never flush anything down a toilet other than toilet-approved materials.


Some clogs can stem from other issues like low water level in a toilet tank or a faulty flapper. To help avoid a clogged toilet, it is best to keep your toilet in good working order, always. It is best to know a little bit about how a toilet works and this in turn will help you the next time you are dealing with a clogged toilet.

Tools Materials Skill Level Estimated Time
• Plunger (ideally a flanged plunger) • Penetrating (nut-breaking) lubricant Beginner 5 minutes to 2 hours
• Closet auger • Thread sealant
• Small wire brush • PVC 3 to 4" and associated fittings (occasionally)
• Rags and towels • Clean out fittings (occasionally)
• Rubber gloves
• (2) 5-Gallon buckets
• Big Gulp cup
• Hand (or drill driven) auger

The toilet is a marvel of modern science. Water, physics, and moving parts getting together to get rid of our unspeakables. The toilet depends on the perfect synchronization of these elements to effectively perform its work. Even when functioning as a well-oiled machine, stuff happens. Toilet clogs can happen, and hopefully they are caught before they spill their dirty water out all over your bathroom floor and beyond.


    1. Unclog a Toilet with a Plunger

    If the first thing you reach for is a plunger, you're right. This is your first move.


    While using a plunger may seem like a no-brainer, there is, like anything, a right way and a wrong way to use one. First, wrap the base of the toilet with old towels. Wear rubber gloves (or better) as you perform any of the work listed below.


    How to Use a Plunger

    Backed-up toilets have a way of dissipating, and blockages are typically not 100 percent total and complete. So be patient. After you discover a clog, wait to see if the water level in the toilet subsides before addressing it with a plunger. If the water level does not subside, grab a 5-gallon bucket and use your Big Gulp cup to scoop some of the water from the toilet. (You don’t want the toilet bowl to overflow as you insert your plunger).


    Insert a flanged plunger (ideally) such that the “cup” of the flanged plunger inserts into the toilet's drain outlet. The “bell” of the plunger (its outer rim) should create a positive seal (a vacuum ultimately) against the bowl's bottom and around the bowl’s outlet. Give the plunger three to four firm thrusts downward.


    In some cases, the toilet may relieve itself at this point. If it does, Yay! You’re done. If not, use a second 5-gallon bucket filled with water (perhaps filled from a nearby bathtub) to wash debris through. Alternatively: Give the toilet a flush, but do be prepared with those towels just in case.


    Newer toilet tanks will utilize between 1.28 and 1.6 gallons per flush (GPF). Not nearly enough to overflow a toilet bowl on its own. (Note: Be more cautious with older models as they will hold more water.) If this still does not accomplish the task, repeat plunging up to three times.


    Dispose of any dirty water and store your plunger appropriately, perhaps using one of those 5-gallon buckets.

    2. Unclogging a Toilet with a Closet Auger

    So the faithful plunger didn’t work. Most clogs occur at the toilet’s trap and yes, toilets have an integral trap. While the plunger is very effective at addressing blockages in the trap, some may extend below the trap to the “closet” outlet found at the floor.


    A closet auger is a type of "snake" designed specifically for toilets. Unlike the plunger, it is made to retrieve obstructions, as much as it is to push them through. Unlike the plunger, it is made to retrieve obstructions, as much as to push them through. It consists of a three foot or so long shaft, capped with a crank (yes, kinda like one of those old-time car kinda things). This shaft and crank drive a coiled spring. At the end of this coil, you'll find a "spring bit," which is meant to grab whatever is backing up your toilet.


    Most closet augers are fitted with a sleeve that will protect the toilet bowl from damage as you work.


    How to Use a Closet Auger

    1. 1) Retract the telescoping shaft from the spring coil of the auger.
    2. 2) Place the auger’s sleeve just at the toilet outlet and insert the spring bit into the toilet's drain outlet.
    3. 3) Apply gentle downward force. Your goal is to get the auger up and through the toilet's trap. As you push downward, crank in a clockwise direction. This action will help drive the flexible snake up and over the toilet's weir (aka trap bend) and down the trap.
    4. 4) Once it has been extended fully, reverse the direction of your cranking and combine it with a light pull on the auger shaft.
    5. 5) If your auger retrieves something, use a small wire brush (found in the plumbing aisle) to clean the spring nut. Work over your 5-gallon bucket.
    6. 6) Follow up with a plunger. If the blockage has freed, flush your toilet or wash down with water from a separate 5-gallon bucket.

    If you are motivated to, follow up with a plunger. If this does not immediately solve your clog, repeat snaking up to three times.

    3. Unclog a Toilet Blockage in the Waste System

    A small percentage of toilet clogs can be traced to issues in the waste or drain system. While a blockage can appear anywhere between the toilet and the home’s main waste and vent stack, we'll proceed by inspecting the branch drain nearest to the fixture.


    Branch lines often contain cleanout fittings. A cleanout is a type of threaded drain fitting that receives a plug. The plug itself will have a male or, in rarer cases, a female "key." Cleanouts provide for just this situation–when a blocked line is suspected, you can access a pipe via a cleanout.


    To proceed locate the main waste and vent stack of the home. Most typically this is a large (4") drain exiting downward through concrete at the lowest point of the house. With this location in mind, follow the path of your toilet back towards the main waste and vent stack. Ideally you’ll have access to much of this run via a basement or a crawl space. If you can identify a cleanout in this branch line, it will likely appear at the point where your toilet drain (often serving other fixtures) transitions from a vertical rise to a horizontal run.

    4. How to Snake a Drain Cleanout

    1. 1) With a rag in hand, liberally spray the outer edge (the threads) of your cleanout plug with penetrating lubricant. Follow the manufacturer's instructions here, but let this oil penetrate for a few minutes. Wipe off any excess.
    2. 2) With buckets nearby, use a pipe wrench to unscrew the plug (counterclockwise) and remove the plug.
    3. 3) If water comes pouring out as you remove this plug, this indicates that a blockage can likely be found between this point and the main sewer line.
    4. 4) Depending on what you find, insert your hand or drill-driven auger and attempt to clear the blockage. Working with a hand auger is similar to working with a closet auger, described above.

    Note: Apply a helping of thread sealant to threads before re-inserting the plug and tightening it down.

    5. Inspecting the Main Waste and Vent Stack

    If you have thoroughly snaked out the branch line, and this has still not relieved the clog, a blockage, unfortunately, may exist at your main waste and vent stack. You will also undoubtedly find a cleanout here. Follow the steps listed above for snaking this location as well.


    Note: When snaking, make sure you are selecting an auger that will reach a reasonable depth into these pipes. Hand and drill-assisted augers are found commonly in both 25- and 50-foot lengths.


    Important! A clogged toilet is often the first sign of issue with the home’s drain system. While your toilet may be clogged, other drains may be as well. To test this theory, move to the lowest fixtures in the home (often another toilet or a sink); are these fixtures draining properly?


    If you have sent your snake down the cleanout at the main stack, and see only a nominal improvement in drainage, you may consider running your auger down the stack via the stack’s main vent pipe accessed from the home’s roof. Yes, slow drainage can sometimes be traced to a blockage in your vent system. Do this while your main stack’s cleanout remains open, and only venture onto the roof if you have experience and are comfortable working on roofs.


    If the issue cannot be found in either appropriate branch lines or in the main waste and vent stack, then you likely have a blockage in your main sewer line. In municipalities where sewer service is provided, you, as the homeowner, will most likely be responsible for any lines that connect into town’s drains, that is–you are responsible if the blockage can be found on your property. It may be wise at this point to phone your local public works department to ensure that there is not an existing known issue with the sewer system in your area.


    As an initial step, and if you haven’t already, sent your hand auger down this line as far as it can go. If you meet resistance, this may indicate that you’re dealing with either tree roots that have grown into the line or an altogether collapsed main. Inspect the "spring nut" on its way back, roots or dirt on the end of the auger could indicate these situations, respectively. Both types of blockages, however, are beyond what can be addressed with a hand auger.


    We will have to turn to a power auger here, available at all major home improvement stores or rental centers. Unfortunately, your clogged toilet has become a more complicated, and potentially more costly, issue. While messy, snaking a main sewer line is not necessarily beyond the skill of many DIYers. Still, it must be approached with caution and extreme care. At this point, you may consider turning the job over to a qualified professional. A good pro has the tools and experience to approach, and more effectively resolve, the issue intelligently and efficiently.

Level of Difficulty

In the largest majority of cases, a clogged toilet is simply a matter of grabbing a plunger. A frequently clogged toilet, however, can indicate issues with the toilet, like an insufficient water level in the toilet tank. This and other items can be addressed with simple tweaks. Frequently clogged toilets throughout the home can point, further, to larger issues in the home’s waste and vent system. Clogged toilets are often only the first signs of issues there.


In very rare cases, you may have to remove your toilet, when attempting to unclog it. While modern plumbing codes call for cleanouts at locations where vertical spans of pipe turn horizontal at fittings, your home unfortunately may not have one where you need it. The act of cleaning out your pipe, in this case, could simply be a matter of installing a new cleanout and using it.

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