Best Options for High-Efficiency Toilets Subscribe Today - Pay Now & Save 64% Off the Cover Price

With water shortages becoming more common, numerous states and nations are enacting regulations to conserve water. The efforts have centered primarily on water efficiency — ways to meet our needs using the least amount of water. One popular approach is the installation of high-efficiency toilets to replace old, water-intensive ones, which consume as much as 7 gallons per flush. If your home has an old toilet, it makes sense — economically and environmentally — to replace it with a water-conserving model that will use about 55 percent less water than a conventional toilet.

Installing a high-efficiency toilet can save you a substantial amount of money by reducing your water bills. Water-efficient toilets also reduce our collective pressure on limited water supplies and, in urban areas, the amount of waste flowing to sewage treatment plants. Less waste lowers the plants’ operating energy and costs.

In rural areas not served by municipal wastewater treatment plants, water-efficient toilets reduce the amount of waste flowing into septic tanks and leach fields, extending the lives of these systems. If you use well water, an efficient toilet will also cut down the run time of your well pump, reducing electrical consumption. Plus, the less your pump runs, the longer it will remain in service.

What Are Your Options?

Water-efficient toilets fit into three categories: single-flush at 1.6 gallons per flush (gpf), dual-flush toilets (1.6 gpf/0.8 gpf) and pressure-assist toilets (1 gpf). Single-flush toilets using 1.6 gallons per flush are now required by law in most new home construction and bathroom remodels. Although the earliest water-efficient toilets had some problems (such as tanks that were too small and lacked sufficient flushing power), most water-efficient toilets on the market today work well.

As the name implies, dual-flush toilets provide two flushing options. Solids are flushed with 1.6 gallons of water. Liquids are flushed by about half that volume — 0.8 to 0.9 gpf. Most manufacturers offer at least one dual-flush toilet.

The third option is a toilet equipped with pressure-assist technology, available from all leading manufacturers. Most common in hotels, restrooms and commercial buildings, these toilets also can be installed in homes. The pressure-assist system consists of a plastic pressure tank mounted inside the toilet tank. It uses pressure from the water supply line to compress air inside the pressure tank. This system traps and compresses air as it fills with water. The compressed air forces the water into the bowl when the toilet is flushed. The pressure-assist unit uses this force to push waste out, creating a vigorous flushing action that whisks away waste and cleans the bowl with only one gallon of water per flush.

The pressure-assist system offers several other benefits. One is that the flush water is contained in a plastic tank inside the ceramic tank, which eliminates the potential for condensation (sweating) on the outside of the tank. This prevents water from dripping onto your floor, causing mold and damaging the flooring. Pressure-assist toilet bowls also have a larger water surface than standard toilets. Having less dry area inside the bowl means a cleaner bowl and less cleaning. These toilets are a bit noisy, however, and you have to buy a whole new toilet if you want this technology. You can’t install the pressure-assist components in a standard, gravity-fed toilet.

How Much Water Do They Save?

Water-efficient toilets save water, but are they really worth the cost? According to the American Water Works Association, on average, Americans flush the toilets in their homes five times per person per day. In a home with 3.5 gpf toilets, this translates to about 17.5 gallons per person per day — just to flush the toilet. For a family of four, using 1.6 gpf toilets saves about 14,000 gallons of water per year. (See Savings From Water-Efficient Toilets.)

In homes equipped with dual-flush toilets, the savings are even greater — as they use only 4.8 gallons per person per day instead of 8 gallons, according to the American Water Works Association. A dual-flush toilet saves more than 4,600 gallons per person per year compared to the old 3.5 gpf models and nearly 1,200 gallons per person per year (or 4,800 gallons for a family of four) when compared to the 1.6 gpf model.

Toilets equipped with the power-assisted system use 1 to 1.6 gpf, depending on the model. Those using 1 gallon per flush perform as well as the dual-flush toilet. Those that consume 1.6 gpf perform as well as the single-flush toilet.

Best Options for High-Efficiency Toilets Subscribe Today - Pay Now & Save 64% Off the Cover Price

Shopping Tips

Water-efficient toilets have improved since their early days in the 1980s. Veritec Consulting has evaluated more than 1,200 toilets. You also can check out Terry Love’s consumer toilet reports for contractors’ and homeowners’ ratings of water-efficient toilets.

Some of the cheaper models may require a couple of flushes to do the job. Paying a few extra dollars for a better unit is worth it in the long run.

One way to assess the effectiveness of a toilet is its gram rating — a standardized laboratory test to determine how many grams of solid material (tested using a soy product) a toilet satisfactorily flushes. A rating greater than 500 grams is good.

To be sure the toilet you purchase will fit, check the distance from the wall to the center of the toilet’s outlet (the pipe into which the toilet drains). This is often referred to as the “rough-in.” It’s usually either 10 or 14 inches. Also, check for rebates. Many water departments, especially those in areas with water shortages, offer rebates ranging from $60 to $80 — sometimes as high as $200 — toward the purchase price of a water-efficient toilet. Dual-flush toilets often command a slightly higher rebate because they’re more efficient.

Look for models with the WaterSense label to easily determine if it’s a water-efficient toilet.

Installation Tips

If you’ve never removed or installed a toilet, you may want to hire a plumber. But if you’re moderately handy, you can probably tackle this job yourself. The only tools you need are pliers, a screwdriver, a wrench (adjustable or socket), a hacksaw, a bucket, a putty knife, a small cup and a rag. The first step is to remove the old fixture. Turn off the water supply to the toilet at the shut-off valve near the wall or floor behind the toilet. Flush the toilet to drain the tank and bowl, then remove the remaining clean water with a small cup and bucket, sopping up the rest with a rag or sponge. Then, disconnect the supply line at the base of the tank. You may need a pair of pliers to loosen the plastic coupling. Be gentle; you don’t want it to crack.

Next, remove the nuts on the two bolts (concealed by plastic caps) that connect the toilet to the floor. Apply some lubricating oil to the threads above the nuts if they’re rusted, then loosen the nuts with a wrench. If that doesn’t work, saw through each nut from above using a hacksaw. Don’t worry about damaging the nut or the bolt; you’re going to replace both of them. Lift the toilet (bowl and tank) off the floor. Get help if necessary, because toilets are heavy — especially one-piece models. For two-piece toilets, you can remove the tank from the bowl by disconnecting two bolts inside the tank.

After removing the toilet, stuff a large rag (that can’t fall into the hole) into the opening in the floor to block gas from the sewer line or septic tank. Scrape off the wax, putty and caulk around the flange (the attachment of the toilet to the floor) with a putty knife. If the flange is damaged, pry it off, and then clean the area beneath it. Screw the new flange into the floor. If your floor is concrete, use self-tapping screws, which cut a hole for themselves as they’re driven in.

If the flange can’t be removed, you can install an adaptor (sometimes called a “superflange”). It fits over the existing flange, creating a secure attachment for a new toilet. Follow the directions that come with the adaptor. Next, insert new 3½-inch flange bolts into the flange or adaptor. Place a new wax ring on the flange or tip the new toilet onto its side and place the wax ring around the opening at the base of the toilet. Be sure to install the correct size wax ring so it will form a seal between the base of the toilet and the flange.

If the toilet comes in two parts, lift the bowl and place it on the flange, making sure the bolts go through the openings in the base. When the toilet bowl is in place, give it a slight twist to seal the wax ring. Place the washers and nuts on the bolts and tighten them by hand. Be sure to alternate tightening, a little on each side, to prevent cracking.

Press down hard on the bowl (or sit on it) to create a tight seal. Tighten the nuts with a wrench until they’re snug on both sides. Repeat this procedure a couple of times until the bowl is tight against the flange when you put your weight on the bowl and there’s no longer a gap between the nuts and the base. You’ve now created a tight seal. Using a hacksaw, trim the bolts off just above the nuts. Replace the decorative caps.

To install the tank, place the gasket, known as the spud gasket, into the bowl inlet. The spud gasket forms a tight seal between the toilet bowl and the tank, preventing leakage. Next, place the tank anchor bolts and washers in the base of the tank. Set the tank on the bowl, making sure the bolts slip into the holes in the back of the bowl. Attach the nuts to the anchor bolts and tighten them until they’re snug, but don’t apply so much pressure that something cracks. With the tank securely in place, reattach the water line.

What Will It Cost?

Water-efficient toilets range in cost from about $50 to a few hundred dollars, but most are $100 to $200. If you can save a little more water while still getting a good flush, it will be worth a little extra money, because you’ll save on your utility bill in the long run.

Cost estimates for installation of a new, 1.6 gallons per flush toilet (includes removal of existing toilet):Materials only: $200Contractor’s total, including materials, labor and markup: $470Costs are national averages and do not include sales tax.

What Will You Save?

Efficient 1.6 gpf toilets can save 3,000 gallons per year per person versus older 3.5 gpf toilets. Dual-flush toilets save more than 4,600 gallons per person compared to 3.5 gpf models. If you have a water-guzzling 5- or 7-gpf toilet (older than 1980), you will really save by replacing it! The EPA’s WaterSense program estimates that if a family of four replaces older toilets with WaterSense labeled toilets, they can save about $1,000 in water bills over 10 years.

This article is excerpted from Green Home Improvement by Dan Chiras. Dan teaches workshops on renewable energy and green building through The Evergreen Institute.