How to Install a Low Flow Toilet

This weekend I completed the final house upgrade for our ecoEnergy Retrofit: do it yourself low flow toilet installation.  We had already paid someone to insulate our basement and interior walls.  But I like to try to do some things myself so after insulating our attic on my own I figured I should at least explore how difficult it would be to install a low flow install a low flow toilet.toilet.  After a quick search on the Internet I was pleased to discover how easy it would be to install a low flow toilet.  I was convinced – I would install both of our low flow toilets.

First, some background.  Last summer Mrs. SPF and I purchased our first home together as a married couple.  When we saw the energy bills we knew we had to Canada-proof our house by making it more energy efficient.  We knew the ecoEnergy Retrofit program was due to expire in March of this year and we wanted to take advantage of the savings on the home upgrades so we had our inspection done.  Prior to getting this done however we were planning on having the inspection done.  The toilets in our new (100 year old) home were pretty low grade so when a box store in town had a sale in July on American Standard low flow toilets we bought two of them and stored them in the new house prior to our move.  These toilets use 4.8 litres (1.3 gallons) per flush whereas “normal” flow toilets use 13-25 litres per flush.  Saving 2.5x to 5.3x more water, and money, per flush is a good idea especially as our city will be implementing water use billing in the next year or so.  Anyhow, we ended up saving a bundle on the toilets.  Costs: Regular Price: $538 + $69.94 HST = 607.94.  Our sale cost: $336.74.   Savings: $271.20.  Retrofit rebate: $130 ($65 per toilet).  Total Cost: $206.74 or 66%.  Total savings on water usage, unknown but given toilet flushing accounts for 28%-30% of household water usage and that toilets have a shelf life of 15-20 years, we should save about $50 per year so $750-$1,000 over the life of the toilets (perhaps more given inflation). The average family of four can save over 30,000 litres (7920 gallons) of water each year which is a LOT of water savings if you install a low flow toilet.

How to Install a Low Flow Toilet

You will need some tools and equipment.  I’ll list what I used, and some alternatives in case you don’t have some of the items I used.

  • bucket, sponge or cloth, rag
  • rubber gloves
  • ratchet set (a wrench set or adjustable wrench will work too)
  • needle nose pliers, adjustable wrench
  • flat head screw driver
  • plumbers putty (optional: see below)
  • all in one box toilet

The toilets we bought had everything in the box that we needed to install our low flow toilets.  There was no need to buy a seat or seat cover, the wax ring you need or the nuts and bolts required.  I strongly suggest you get a similar toilet as it makes shopping a no-brainer.

Step 1 – Remove the Old Toilet

  1. Turn off the water supply to the tank.  There is a small shut off valve located beside the toilet attached to the piping coming out of the floor.  Assuming your old toilet flushes the water is turned on.  So turn the sOld toilethut off valve (usually to a horizontal position).
  2. Flush the toilet to drain the tank.
  3. Put on the rubber gloves, grab your sponge or cloth and soak up the water that remains in both the toilet tank and bowl.  You don’t have to use gloves, but this is a used toilet.  Be sanitary.
  4. Unscrew the water supply line from the toilet bowl.  You may need to loosen the connector with pliers or a wrench.  Oddly, the instructions I read said disconnect the line prior to sponging out the tank which didn’t make sense to me as the water would have drained onto the floor.
  5. Detach the old tank.  I used the ratchet wrench for the nuts and the flat head screw driver to hold the bolt heads inside the tank in place.
  6. Remove the old tank by lifting it off of the toilet bowl.  Toilets are heavy, so lift with your legs and be careful to not throw out your back.  If you are unsure about the weight, get someone to help you move the tank when you remove it from the work area.
  7. Free the old bowl.  Use your screwdriver to pry the caps off of the bolts on either side of the toilet base.  Remove the nuts on the floor bolts – I used the ratchet wrench for this as well.
  8. Rock the toilet bowl back and forth to break the seal between the toilet and the flange (the black hard plastic thing attached to the floor that leads to the plumbing).  Remove the toilet bowl from the work area.  The bowl is much heavier than the tank, so again, take care and get help if you need help.Old toilet
  9. Remove the bolts from the flange and clean up the flange if thee is any leftover wax, dirt or grimeon the flange.
  10. Inspect the flange to make sure it is in good condition.  For us, one was in fine condition but the other was broken a bit so I had to use some strong adhesive to re-attach it.  I probably should have replaced the flange but this is not a recommended DIY project and likely requires a plumber, who I didn’t want to pay.  My “fix” worked pretty well.
  11. Clean up the floor.  Chances are the floor is dirty where the toilet used to sit.  I cleaned up the floor as I won’t have another opportunity for 15-20 years and if using plumbers puddy in the next few steps you want a clean surface to work on.

Step 2 – Install a low flow toilet bowl

  1. Lay the new low flow toilet bowl on a blanket (to avoid scratching it) upside down.  Place the wax seal (and horn)
    around the discharge hole underneath the bowl.  It should stick to the bottom of the toilet.  The instructions I got online also suggested using plumbing sealant around the outer edge of the bottom of the toilet bowl, however, the Home Depot guy told me that if I was installing the toilet on linoleum flooring I shouldn’t use theinstall a low flow toilet. puddy as it would cause the flooring to get ripped up if I ever needed to remove the toilet bowl.  So I skipped this step.
  2. Put the closet bolts that come with the toilet in place in the flange channels about 6″ apart.  Turn the bolts 90 degrees so they don’t slide out of the flange channel.
  3. Turn the bowl right side up (Mrs. SPF helped me with this as the bowl for our toilet was 70 lbs) and position it over the floor opening.  Be careful to line up the holes in the base of the bowl with the bolts on the floor flange.  The discharge on the bowl should fit into the hole in the floor.
  4. Apply pressure to the bowl to ensure you get a good seal.
  5. Attach the bowl to the floor using the nuts and washers that came with the toilet.  Note: don’t over tighten these nuts as the procelain can crack pretty easily.

Step 3 – Install a low flow toilet tank

  1. Our toilet tank was ready to be installed when we bought it.  However, if yours is in pieces you’ll need to install the flush handle, the tank ball and the float ball.
  2. Flip the tank upside down and install the large rubber gasket over the threaded outlet on the bottom of the tank.
  3. Pick up the tank and place it on the bowl so the tapered end of the rubber gasket fits into the bowl water inlet opening and the tank mounting bolts line up and fit into the mounting holes on the bowl base.
  4. Use the metal washer / nut combo to attach the tank to the bowl.  Again I used the ratchet wrench for this.  I alternated tightening each bolt in order to evenly distribute the pressure, again, to avoid cracking the porcelain.
  5. Install the water line to the tank.  Don’t over tighten.  I’m not sure why, but the instructions I read said not to.
  6. Turn the water supply shut off valve back on and test the toilet!
  7. You will likely need to adjust the water level.  You need to submerge the float cup under water for 30 seconds and then use the water level adjustment rod (twist it) to get the float cup to the right spot.  For our toilets there flush valve (a tall tube used to make sure overflow doesn’t occur) was taped so I could tell where the water level should be set.

With these instructions you should be able to install a low flow toilet easily.

photo credit: Newhaircut photo credit: qnr

15 thoughts on “How to Install a Low Flow Toilet

  1. great post! It is amazing to me how many people haven’t taken the “plunge” yet on moving to a low-flow toilet..

  2. Especially with the sales at the box stores, coupled with the retofit program – we got 2 really nice, good brand toilets for VERY cheap and they WILL pay for themselves. It looks like all of our retrofits, when including the ~$3500 rebate we’ll get, should pay for themselves in 7-8 years but we’ll reap the benefits for 12-15 yrs after that. Money in OUR POCKET!

  3. Thanks for these instructions! As simple as they are, and as experienced I am in replacing the various components of a toilet (I’ve done that many times), I’m still hiring a plumber to replace my toilet just because I don’t trust myself enough. I’ve had enough DIY projects go wrong that I now hire professionals unless it’s something that I can’t botch up. Coincidentally we ordered a low-flow toilet about a week ago. Our water isn’t metered so our motivation is purely environmental as well as the desire to have a high-performance toilet. The low-flow toilets are actually a lot more resistant to clogging and give a much more powerful flush than standard toilets. They got a bad rap for a while in the early years (everyone called them “double-flush” toilets because you had to flush them twice), but the new ones are a totally different animal. I used EPA’s WaterSense site to find a WaterSense-certified low-flow toilet; I chose the Toto Eco Promenade.

    1. I read good things about Totos.
      Brad – i’m not the handiest guy in the world. I don’t like to deal with electrical much and I usually steer clear of plumbing. That being said, once I was able to turn off the water valve at the base of the toilet, flush once and see that our pipes didn’t explode, the rest of the install was quite easy (save lifting a 70lb bowl into place – it doesn’t exactly have handles! So Mrs. SPF gave me a hand on making sure it didn’t get dropped).

      The other nervous point was after I put the thing together and I turned the water back on and flushed – if you’ve messed up you’ll learn quick I presume. In the end it was as easy as I research and discussed here. If you do decide to install your own feel free to bounce questions off of me if you like. I don’t charge as much as a plumber ;)

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  5. I have replaced a couple of toilets with great results. More recently I had one that just about cost me my sanity. I installed it, and water leaked out of the bottom. I tried again with a new wax ring, still leaked. The flange was a bit cracked, so I bought a superflange and installed that. Tried again with yet another new wax ring, and it still leaked. Then I tried the waxless ring. Still leaked. After several days of frustration/confusion I finally examined the new toilet, and found a small flaw way up inside! It was the toilet all along.

    After a quick trip to Home Depot to exchange the toilet, all is well now. I learned not to always assume that if something goes wrong with DIY it must be my screw up!

  6. Well-done, SPF.
    I’d probably need to add some in-between points, like “go back to the garage to find the right tool that someone took out of my bag” and “get up to stretch aching back” and “go back again to get the teflon tape”…

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  8. Last November my fiancé and I bought a home together. Our Realtor told us that it was a fixer-upper, but we had no idea that the plumbing was so lousy. The realtor suggested that we call a professional, we did and in three days everything was handled. What I liked the most was their desire to help us in every way.

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