How To Replace A Toilet

With a name like John it’s no surprise that I’ve installed a slew of toilets to date. It’s not glamorous work, but somebody’s gotta do it. In fact a few weekends ago I got roped into helping my dad install one in his newly remodeled bathroom, so I figured while I was at it I might as well take a few pictures and write up a quick and dirty (pun intended) toilet-installation tutorial for your convenience. Of course our disclaimer would be that every toilet is different and can therefore call for a slightly varied installation technique so be sure to read all the directions that correlate to your throne before proceeding. Here’s the potty play by play:

Step One: Before hitting up Lowe’s or Home Depot for your new toilet, measure the distance from the back bolts (at the base of the toilet nearest to the wall) and the wall behind your toilet. This is called the toilet’s rough-in and most toilets are designed with a 12″ rough-in. One of our toilets was actually a compact version so be sure not to skip this step of you’ll end up with a toilet that won’t line up with your existing plumbing.


Step Two: Once you’re home with the appropriately sized replacement toilet it’s time to remove the existing one. The first step is to turn off the toilet’s water supply (usually located behind the bottom left hand corner of the bowl). Then just flush the toilet to empty its tank, holding the trip-lever down to let all of the remaining water to run out. Remove the small amount of lingering water in the tank and bowl with a sponge or a few rags to ensure that they’re both totally empty.

Step Three: Use a wrench to remove the coupling nut between the existing toilet tank and its water supply. You might need to hold the fill valve with pliers from inside the tank to keep it from twisting. Next remove the toilet bowl which is typically fastened to the floor with two bolts (although some have four). If these bolts give you any trouble you can always carefully remove ’em with a mini-hacksaw. Then just loosen the bowl by rocking it to break the seal with the floor and carry it straight outside (our old pea green one lived in the backyard until we could take it to Habitat For Humanity’s ReStore a few days later). It helps to have someone on hand to immediately stuff rags into the newly exposed toilet flange (the hole in the floor that can smell pretty nasty if left unplugged). Of course be careful not to lose a rag down the hole.

Step Four: To fully prepare for the new toilet, thoroughly remove any old wax from the floor and the flange with a screwdriver or a putty knife. Then unscrew the old bolts that hold the toilet down and throw them away (it’s a hard and fast rule to never attempt to reuse them). Oh and now’s a good time to clean and paint the wall behind the toilet while you have full access.

Step Five: Temporarily place the toilet in position on the floor over the flange to ensure that it fits and check that it looks level. View it from all possible angles and, if necessary, use plastic shims to get things level. Then it’s time to install the new bolts to hold the toilet bowl to the floor. If there are openings for the bolts in the toilet flange, just slide them right through. If you have a cast iron piping system, these screws can be drilled directly into the wood floor, but be sure to install the bolts so that they’re the same distance away from the back wall behind the toilet.


Step Six: Installing your new toilet pretty much goes backwards from the steps above which detailed removing the old one. Be super careful with your new bowl and tank since they can chip and crack super easily (especially if you get overzealous when you’re tighten bolts). You should have purchased a wax ring kit along with your new toilet, and you’ll want to follow the instructions that come with that to the letter (this is imperative to avoid leakage that can rot your floor and basically ruin your life).


Step Seven: Now it’s time to remove the rag from the hole in the floor (hold your nose for this step) and carefully place the wax ring around the outlet in the bottom of the toilet (with the wax-side on toilet). Press it slightly to be sure it holds, since you’ll be flipping it upside next. One you’ve carefully flipped it over, line up the toilet over the opening the in floor (the flange) and the bolts. The bolts that hold the toilet down should pass through their openings in the bowl base, and wax ring should make contact over the flange. To set the bowl onto the floor, rock it carefully from front to back and side to side while pushing down firmly. Don’t raise the bowl from the floor while making adjustments or you’ll literally have to replace the wax ring all over again as the toilet will leak to no end each time it’s used. It’s happened to us.

Step Eight: Drop washers over the bolts that hold the toilet to the floor and tighten the nuts with your fingers (the reason you should only finger-tighten the bolts is due to the fact that over tightening with a wrench can crack the toilet- which is seriously bad news).


Step Nine: If the toilet tank hardware comes separately, install it using the accompanying directions. Then take the rubber spud washer (the big rubber thingie that fits between the tank and the bowl) and set it right into the flush valve opening in the bottom of the tank. Pick up the tank and lower it gently into place on the back of the bowl. Then install the two long tank-mounting bolts from inside the tank, sliding them down through the holes and tighten the washers and nuts gently and evenly until they are snug. Viola- it’s starting to look like a real toilet…


Step Ten: Now it’s time to connect the tank’s water supply to the inlet valve on the bottom left of the tank. You’ll probably have a coupling nut laying around just for this purpose. Then turn the water on and watch the toilet tank as it fills up. If there are any leaks, gently tightening the bolts should fix ’em in a flash (initial leaks are actually pretty common, but locating the leakage and tightening the bolt ever so slightly is usually all it takes). At this point you should also be sure that the tank is filling up to the correct level (about 3/4″ under the top of the overflow tube). Then just tighten the bolts that secure the bowl to the floor one turn beyond hand-tight (with a wrench, but just one turn- I mean it!).


Step Eleven: Test your installation by flushing the toilet and watching that beautiful swirling water do its thang. Double check for water leaks on the floor (and retighten the bolts that produce even the slightest drip just slightly). Then pop on the toilet seat and the toilet tank cover and do a little victory dance. You’ve earned it.


Need more toilet help? See some additional instructions at and


  1. says

    Oooohhh!!! Just what I need! Thank you so much! I’ve been meaning to lay under floor heating and a new tile floor in the tiny upstairs bathroom and with that I obviously need to remove the toilet. Last time I had my neighbor help me but didn’t pay enough attention to what he was doing and he’s since moved… Now that I have your tutorial I can do it myself! Now I can’t wait!!! Yay!

  2. Lindsay says

    Thanks John! Perfect timing actually… my husband and I have started demo and the toilet is the last thing standing in the “old” half bath. I’m sure this will come in handy!

  3. MaryB in Richmond says

    I will never ever ever ever need to know how to install a toilet BUT I’m glad I read all the way through this or I would have missed the glamour shot at the end!!

  4. says

    What great timing — I just picked up a new energy efficient dual flush toilet at Costco (for $179.99!) and asked my husband on our way out, “You know how to replace a toilet, right?” This will be most helpful — thank you for posting!

  5. says

    My dad is my toilet installer and he hates those wax rings….they are sticky and messy. He bought one this last time that wasn’t waxy (I don’t remember what they called it, though) and he thought he’d try it. Worked like a charm without all of the grossness. He got it at Lowe’s.

  6. says

    This was one of my very first DIY lessons, and it’s come in handy more often than I ever would have imagined. It’s kind of like changing a tire–not the most glamorous of tasks, but definitely knowledge everyone should have tucked away, just in case!

  7. says

    When you’re at the store make sure to get new brass bolts (the solid brass are less than a dollar more), check to see of the new toilet needs a longer/shorter water supply line, and now is also a good time to replace the shut off valve if the old one is cracked, rusty or cruddy.
    I’ve used the waxless rings before too and liked it but not all stores carry them.

  8. denise says

    curious – where did you find a toilet that wasn’t a 12″ standard rough-in? ours is an 11″ and no lowe’s or home depot in our area sells them. i’ve tried a local plumbing supply store as well, and no dice.

  9. says

    Thanks for the tutorial. I just purchased my first house and have never had to these kinds of things before. The bathroom was my first fixer project :)

  10. Liz says

    I am going to be helping my mom install a new toilet in her bathroom pretty soon, but I am curious if we should install the toilet after we put down the new tile floor or before?

    • says

      After! You want the tile to go under the toilet and to cover as much as possible (except the hole for drainage of course) so it’s seamless and the floor is protected against leaks under the bowl!


  11. Daniel Rodriguez says

    I’m going to have to do this at my in-laws in a couple of weeks. They’re also needing to put tile down on the floor. Should I change the toilet before or after the flooring? Or pros and cons to either befor or after? Thanks for the post!

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