Room for Change: Toilets

In our Room for Change series, we look for relatively inexpensive ways to make sustainable, climate-mitigating improvements to our homes that have a big payoff. When it comes to toilets, we believe we’ve found the royal flush of sustainable ideas. 

No matter who we are or what kind of homes we have, everyone needs a place to “go,” which means that investing in toilets in a more environmentally thoughtful way can make a big difference. 

Low Flow

According to the Environmental Protection Agency (EPA), an astounding thirty percent of a home’s indoor water consumption can be attributed to toilets. Thirty percent! Older toilets use up to six gallons per flush, whereas new models use 1.28 gallons. Replacing an old toilet with a new one is therefore a relatively simple way to reduce home water consumption. This is especially important if you have a toilet that runs or leaks. Leaky toilets (And sinks! So pay attention here, too) can waste up to 180 gallons of water PER WEEK. 

The EPA’s WaterSense program estimates that replacing old toilets with more efficient models can “reduce water used for toilets by twenty to sixty percent — that’s nearly 13,000 gallons of water savings for your home every year!” Newer toilets can also save more than $110 per year in water costs, or $2,200 over the lifetime of a toilet. And here’s the big, super fact that WaterSense calculated: “If all the inefficient toilets in the United States were replaced with WaterSense-labeled models, we could save 520 billion gallons of water per year, or the amount of water that flows over Niagara Falls in about 12 days.” And keep in mind that they are calculating this with the EPA low flow standard set in 1992, which is 1.6 gallons of water. If we installed the newer, more efficient models that use only 1.28 gallons, even more water would be saved. 

No Flow

The other option, of course, is a toilet that uses NO WATER. If your home (or a home you are designing) allows for it, you could install  composting toilets. As implied by their name, these systems compost waste on site, turning it into stable dry and liquid end-products that can be used as fertilizer. The toilet looks ordinary, but instead of having water in a bowl that moves waste through pipes when flushed, composting toilets have a chute that leads directly to a plastic holding tank. The website of Clivus New England (a major composting toilet manufacturer and installer)  explains the science: “The Clivus system uses aerobic mesophilic decomposition to slowly break down both urine and feces into stable compounds within the composting system.” 

When I talked about composting toilets with Newell Isbell Shinn, South Mountain Company’s Director of Production, he told me, “Every time I fill out an environmental footprint* for our family, I see how having a composting toilet makes a huge impact on our water use. It’s nonsensical to pump clean, fresh water into the house, pollute it, and then pump it back out of the house. Having a composting toilet has minimal impact on my daily life. A composting system actually pulls odors away from the bathroom, leaving a cleaner, fresher space. Some people use shavings with every use, but you can also just add shavings to your Clivus weekly or monthly. And there are varying degrees of interaction you can have with your composting toilet. You can be hands-on, or you can have a service contract with Clivus New England where they come and deal with it.”

He does concede that installing composting toilets is a bigger deal than putting in conventional toilets. The “straight drop” composting toilets must be situated directly above the waste catchment area so toilets in a home must be designed to be directly above one another or have a pipe that drops straight down and directly into the basement. And even foaming composting toilets, which use foam to move waste, can only move it a few horizontal feet. This expands the possibilities for where waste can be collected and stored, but not by a lot. (A conventional toilet using water can move waste for “a much more significant distance in the home.”) This makes retrofitting an existing home with a composting toilet challenging, and Shinn admits that, “In the 7 and ½ years I have worked for South Mountain, we have not installed a composting toilet. It may be because people can’t quite get over having a storage tank with waste inside their homes. Mostly, though, I think we got out of the habit of designing them in. This conversation is an inspiration to start again!”

When my husband and I were designing our home, we were not put off by the idea of waste in a tank in the basement, and our original concern that composting toilets always needed “action” (what if we had to be away for two months?)  turned out to be a myth. What ultimately drove our choice to use a conventional water toilet system was the design factor (the “straight drop” system’s requirement that composting tanks sit directly below our toilets) and the installation cost, which at the time was too much for us. 

When I spoke to Joe Ducharme at Clivus New England, which installs and services most composting toilet systems on the island, he told me that installing a typical residential Clivus system currently costs between $20-$30,000. The maintenance costs for a Clivus depend on the demands on the system. He said, “For a McDonald’s, we are there twice a month, but some of our customers only have us come out once a year, spending about $300 for this.” The West Tisbury Library, which has a foaming compost system, has Clivus New England service their system about four times a year. If you choose to follow the no-flow path, Clivus New England are the people to talk to. 

But, I wondered, if you choose the low flow path, which is the best toilet to buy? I reached out to nine local plumbers to talk about conventional water toilets, because who knows better than the folks who install and fix them? Five did not call me back. Fair enough; It’s winter, and they’re probably busy fixing broken heating systems. Two chatted with me for a few minutes but said they didn’t want to go “on the record.” Finally, I found two plumbers who were generous with their time and willing to share their experience. Curtis Lavigne and David Bettencourt had a lot to share, all of it valuable. 

First, every plumber (on and off the record) gave Kohler the highest marks for longevity, effective flushing, and overall performance. Curtis told me, “I say Kohler hands down. I get all these fancy jobs for Toto [a high end toilet brand]. The way they mount to the floor, it’s a total pain. And each model has a different mounting spec. Plus with Toto  there are so many mechanisms with so many variations. They are hard to stock parts for. Meanwhile Kohler toilets have more universal systems and parts. And the ones that only use 1.28 gallons per flush, flush really well and hold up.”

David said he liked Kohler above all other toilets as well. He explained, “They have a siphon, so when you flush the water, it points toward the outlet hole in the bottom of the tank. It doesn’t swirl. This makes them much more effective.”

David advises always buying toilets from a plumbing supply company, rather than from a low-cost superstore like Home Depot or Lowe’s. He explained that while these stores advertise having higher-end products like Kohler toilets, and their models look exactly like the Kohler models at a plumbing supply, the superstore versions are made more cheaply and won’t hold up as well.  

While he didn’t agree with Curtis about Toto, David did have reservations about wall mounted toilets. These are the toilets where the frame and tank are inside the wall, and one only sees the bowl. David said, “Yes it is more streamlined and easier to clean around, but to work on them, you only have an access plate area of about 4×8 inches. You have to have little fingers. Plus, you cannot put these toilets on outside walls, as the tank will freeze. In my opinion, they are problematic. Plus they remind me of jail toilets.” 

As for the single/double flush toilets that have two buttons on the top (one using .8 gallons per flush, the other 1.6 gallons), both Curtis and David wondered how many people really take advantage of both flushing options. While they have no evidence, both suspect that most people opt to use the double more often than the single flush, just to be on the safe side. “This is why I often recommend just getting a super efficient toilet that uses just 1.28 gallons.” Curtis says.

Curtis also pointed out another good reason for Martha’s Vineyard residents to invest in low flow toilets: less water means less stress on our septic systems. “So many people here have septic systems, and it’s not good to be sending extra water into the septic if you don’t need to. Too much water can diminish the septic’s ability to effectively treat the wastewater. And it’s is more wear on the system.”

When it comes to cost, replacing most toilets (unless there is significant damage — rot, etc. — around the base of the existing toilet) takes about an hour and costs a homeowner the price of a toilet plus their plumber’s hourly rate. So replacing your toilet is a low-cost investment with a big upside: saving hundreds of gallons of water a year and the energy it costs to pump that water.

My advice, in a nutshell

1. Even if you don’t/can’t invest in a new toilet now, fix your leaky toilets … and sink.
2. Invest in a WaterSense low-flow toilet if you do replace one.
3. Buy from a plumbing supply company, where you know you’ll get the best-made products.  If your home and budget allow, invest in a no-flow, composting toilet.

There are now many sites dedicated to helping you calculate your environmental footprint. A few we like: 

• Conservation International
• CarbonFootprint.com
• Berkeley’s Cool climate calculator