s How to Choose and Install a Low Flow Toilet - The Kim Six Fix
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How to Choose and Install a Low Flow Toilet

How to Choose and install high efficiency toilet. Everything you need to know before heading to the home improvement store.

If you are using toilets installed anytime in the last century (okay.. it sounds crazy when I say it that way.. but I mean “Pre-2000”) it is pretty likely that you are either using way more water than you have to, or are using outdated technology which conserves water but is not very efficient at flushing waste or frequently clogs.

The toilets in our house were 1988 monsters using almost 4 gallons per flush. (For perspective, todays standard of “low flow” is 1.28 gallons.) If you are using a toilet from the 70s, you could be using as much as seven gallons!  SEVEN GALLONS!!  That is the equivalent of flushing a modern toilet more than five times.  (Side note: if you are using toilet from the 70s.. it is probably pretty gross by now and you should change it anyhow!)
Low Flow Toilet Options
Today’s low-flow toilets are pretty amazing, considering that some of them use as little as 0.8 gallons of water and yet have astounding ability to flush a small pony down the drain (okay, maybe that is a slight exaggeration.. but they are much more powerful than their previous water saving counterparts.)

I’ve previously written about the pros of saving on your utility bills, and so this project was a no brainer.  And to make it even better, our utility district has a $50 rebate on any Water Sense toilet, so this project practically paid for itself.  (Most water districts do offer rebates, just check with your local company.)

In our upstairs bathrooms these are the toilets we had:
High water usage toilet
You can see how large the tank was in order to hold all the water.

It was just a huge WASTE even though they weren't in the most commonly used bathrooms.  I chose a new 1.28 gallon per flush American Standard model as a replacement.   I took a side by side photos with the new one (the ruler is for reference) to show you the difference in tank size when you covert to a water efficient model
Replacing low flow toiletYou also will notice the tank is tapered, to give you more flushing power with less water.   Plus it takes up less space in your bathroom, which is never a bad thing right?

So how did I decide exactly which one was the best choice for me? 

When figuring out what kind of toilet you want to upgrade to, there are lots of things to keep in mind.


1. Flushing Power:  This is a big reason a lot of people haven’t upgraded. They believe the toilets with less water just won’t work as well.  And it was true that the 90s versions of “low flow” toilets actually didn’t FLOW very well at all.. often requiring multiple flushes.  But changes in toilet design have helped alleviate that problem and now you can even find pressure assisted toilets which use a pump system and not just gravity to aid in the flushing process.  Modification of tank shape, and changes to the shape and size of the outflow drain also make modern toilets much more powerful with much less water.

Home depot flush power ratings
 When purchasing a new toilet many buying sites offer ratings on the ‘flushing power’ of different models so you can compare apples to apples.

2. Water Usage:
The standard unit of water usage in toilets is GPF or Gallons Per Flush.  These numbers aren’t 100% accurate because the actual amount of water used in each flush can vary based on how high or low you set the float or if anything in the tank displaces the water, but they are pretty close.  As I mentioned before older models can use as much as 7 gallons, while today most manufactuers are shooting for the 1.28 GPF mark which is suggested by the EPA.  (Federal Standards for new toilets require 1.6 GPF.)

If you want to qualify for a rebate from your utility company, chances are you will need to buy a WaterSense certified toilet.  These are actually pretty easy to find in any home improvement store, you just want to look for the WaterSense LabelWater sense toilet logo

3. Single/Dual flush:
Another recent change to the way toilets function is the development of dual-flush technology.  This is a mechanism by which you flush one way for liquid waste and another way for solid, since flushing solid waste usually requires more power.   You can find new toilets with this technology integrated into it, or there are even retrofit kits to modify your existing toilets to use dual flush.

4. One or Two Piece: 
This is an aesthetic and functional decision.  Most residential toilets are two pieces: A tank and base with a bowl.  But single piece toilets are available and tend to be easier to clean and have a sleeker look. They tend to be more expensive, but they function very similarly to a standard two piece toilet.

71A+kDcIVpL SL1500
5. Bowl Shape:
This too is an aesthetic and functional preference.  Elongated bowls tend to be more comfortable and are less prone to “misses” but they do require more floor space.  Round bowls are good for smaller bathrooms.  You need to consider your bowl shape when buying replacement seats and lids.
Round Long Bowls wLabels1 300x150

6. Total Height/Bowl Height/Rough-In Distance:
These are a few factors that may be non-negotiable when it comes to selecting a replacement toilet.  Because my old toilet was installed beneath a countertop I needed to the tank height to be a certain number of lower.  That really limited my selection.

Another important measurement is the bowl height.  This determines how far down you have “squat” to sit on the toilet itself.  Standard toilets have heights between 14 and 15 inches, while ADA and handicapped accessible toilets (known as “chair” or “comfort” height) have to be a minimum of 16.5 inches tall.   There aren’t code requirements in residential restrooms, but most commercial spaces must had ADA compliant toilet heights. Toiletbg ada approved
The other measurement you MUST KNOW when you select your toilet is the rough-in distance.  That is how far your drain and mounting bolts is from the wall.  Most toilets have a standard rough in distance of 12 inches, but in some smaller bathrooms, it can be closer to 10.  There are even some models that require 14 inches of clearance.   Cfig04 engYou can always install a new toilet with a smaller rough in distance (it will just float farther away from the wall) but you can’t go the other way.  If your toilet requires only 10 inches of clearance, you can’t install a 12-inch rough in toilet.  In my case, my replacement toilet was a 10 inch rough in (that was the only one they had with my height requirements) but my bolts were 12 inches from the wall.  There is now a slightly larger gap between the toilet tank and the wall, but it isn’t a big deal.

7. Branding/Other cosmetic factors: 
This is the final decision you need to make once you have figured out everything else on this list.  Unlike everything else I mentioned, this is SOLELY personal taste.  Toilets come in all sorts of shapes and colors.   They also come in a variety of brands and price points.  Obviously standard toilets are white but depending on your other bathroom fixtures, ivory, cream, or even black may be a more appropriate fit.
51DdqrZnkWL SL1000
My powder room toilet is designed to exactly match the pedestal sink in that room.  That is a completely stylistic decision, it has little to do with functionality:

So how hard is it to replace a toilet?  Not hard at all.  It is probably a two person job since the porcelain is pretty heavy, but you don’t need to be a master plumber or anything.

Before following this tutorial, please check with your local building codes. In the state of California, toilets in single family homes built before 1994 can only be replaced with low flow versions and often require a permit and inspection.

First things first.  Turn off the water and flush the toilet to drain all the water out of the tank.  Using a towel or sponge, sop up any extra water and then disconnect the water supply line foom the tank. (Leave the water line attached to the wall.. we are going to re-use it!)
Toilet water supply
Now, for ease of removal we are going to disconnect the toilet tank from the base. (Unless you are the Incredible Hulk you will want to do this.. toilets are HEAVY and unruly.  Taking them apart in pieces is much easier.)

You can see my old toilet tank was held on by three bolts.
Toilet Tank attachment

With the tank out of the way this is the perfect time to paint behind it.  I never could fit even a small brush behind the tank, so you can see how the wall was never painted.  Toilet tank removal

Toilets are only held to the floor by gravity and two long bolts.  The bolts are disguised under these two covers at the base of the toilet, under the bowl:Toilet bolt caps
To remove the old toilet base, unscrew the nuts and lift the base straight off
Removing toilet bolts

Our old toilet was held in place with  bead of caulk.  This is actually NOT recommended.  If this is the case with yours, make sure to cut the caulk seal with a utility knife or you won’t be able to lift it up.  Once you have the bolts removed and the caulk seal broken, you can lift the base straight up and take it away.  You most likely will end up with something like this:
Toilet Wax Ring and FlangeYou will be left with the old wax ring (which seals the toilet drain to the floor drain and keeps sewer gas and water from leaking out), the flange (which is attached to the floor and holds the toilet in place with two large attachment bolts) and possibly a wax ring insert or “funnel” (which redirects the waste to the drain line.) You want to get rid of as much of the old wax as possible. It is also possible that your wax ring and funnel will either fully or partially pull away with the toilet. In that case you may see more of the flange.

Remember when you scrape away the wax, you want to get all the way down to the flange.  Here is what ours looked like with the wax removed, but the insert still in place:
Removing a wax ring with insert
My toilet flange was orange, but typically they are white.  Here is what one looks like when it is new. You want to get as much wax off as possible, but you don’t have to get them perfectly clean if you are immediately re-installing a toilet.  You also can reuse the bolts if they are in good shape and not bent or rusty.

Our toilet was actually re-installed after the floor was tiled less than 3 years ago so mine were pristine.. that is also why my old wax ring didn’t look too bad.  If your toilet has been in place more than 5 years I would suggest using new bolts.  Your new toilet will come with new ones so it is not a huge deal to replace them, but I just lucked out.Toilet flange
Finally, don’t forget to scrape up any old caulk if there is any.  All toilet bases don’t actually have the same footprint so you may not cover up the old caulk lines with the new toilet base.  **See the end of this post for more information about caulking around the the toilet. 
Removing caulk

Now to prep the toilet for installation.

First, apply the new wax ring to the bottom of the new toilet.:
Replacing wax ring on toilet
Wax rings come either plain or with the funnel already embedded in them.  If you drain flange is AT OR BELOW floor level you MUST use a ring with a funnel.  If your flange is ABOVE the level of the finished floor you can use a plain wax ring since the toilet drain and the floor drain will come into contact with each other. In my case, because the area around the flange was not tiled, but the finished floor was, I needed to use a funnel.

Luckily almost all toilets you buy at big home improvement stores include a wax ring with funnel in the box along with the toilet, but you want to double check you have the correct kind before leaving the store.  if you aren’t sure of the type, you can always pick one up.. they cost a whopping 89 cents: Cheaper than a return trip! 
Wax rings
 The wax ring is so sticky that it will stay put one you press it on to the toilet drain. (You can also add it to the flange and try to set down the toilet onto the ring.. it doesn’t really matter.)
New Wax ring installation

Set the toilet into place over the bolts (this is probably a two man job. One to lift the weight and one to help align the holes over the bolts.)  Remember ONCE YOU SET IT DOWN YOU SHOULD NOT MOVE IT!!  You can break the wax ring seal if you move the toilet base.. so take the time to get it where you want it the first time!

Once you have it in place, press it down pretty hard with a slight rocking motion to embed it into the wax properly. You should be able to get the toilet to rest on the finished floor, it shouldn’t be floating above it by resting on the wax ring. New toilet installation

Tighten down attachment bolts (hand tight.. don’t use a wrench or you could crack the porcelain!) Installing toilet

Reattach the toilet tank (This model only had 2 attachment bolts):
Installing toilet tank
Finally put the tank lid back on, and attach the seat (following manufacture instructions.. all seats are slightly different).  Turn the water back on, let it fill and flush it a few times..watching carefully for any leaks either between the tank and the base, from the waterlines, or from under the toilet itself.

Low flow toilet installationAin’t she purdy?    And I’m saving 50% more water with every flush!


**There is a long-standing debate about whether or not toilet bases should be caulked.  In many states it is a code requirement that commercial toilets be caulked for sanitary reasons (Bad Aim!)  However, most plumbers only caulk around the front three sides so if there is a leak you can detect it (vs. sealing the water in under the toilet and causing the floor to rot.)  If your floors aren’t level and you are worried about your toilet rocking, caulking is a good way to secure the base.  You also can use a rope of plumbers putty under the edge of the base if you don’t want visible caulk lines.

In my case I chose NOT to caulk when I installed my toilet since the fit was really tight and level and I didn’t think it was necessary.  However, if you do want to caulk this tutorial from Family Handyman is the best one I’ve seen for using caulk to form a strong seal (vs. just cosmetically filling the gap between the toilet and the floor.)

Image sources:
Title (modified), water savings,  bowl shape toilet height, rough-in distance, wax ring and flange 

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