The High Efficiency of Low-Flow Plumbing

By Ygrene on July 20, 2017
antique faucet

Low-flow plumbing may not seem like a vital efficiency improvement. However, considering that homeowners use showers, faucets, and toilets multiple times every day, such an upgrade makes perfect sense. Why are low-flow plumbing fixtures worthwhile? They can lower your water bill significantly. By some estimates, it takes a year or less to pay for the cost of buying and installing low-flow faucets and showerheads.

The Environmental Protection Agency (EPA) puts the savings into perspective: if every American switched to low-flow fixtures, the country would collectively save about $8 billion on water costs per year. Those considering a switch to low-flow models should also consider the cost of heating water.

Because hot water must be warmed by electricity or natural gas, this adds to the energy bill. Low-flow equipment, especially showerheads, can reduce these extra energy costs because they use less hot water.

How Much Water Can You Actually Save?

The amount of water you can save from low-flow plumbing will vary, depending on the model that you choose. In general, however, here is a rundown of savings by the gallon:

  • For showerheads, efficient models have a flow rate of less than 2.5 gallons per minute. Newer models drop that number down to two gallons per minute. This is significantly less than older models, which can release more than five gallons per minute.
  • Low-flow toilets average less than 1.6 gallons per flush, as opposed to 3.6 gallons in an older toilet. Efficiency-geared toilets may also have a half-flush option for liquid, and full flush for solid waste. This extra control is usually in the form of two buttons on the top of the toilet tank.
  • Newer faucets have a flow rate of 1.5 gallons per minute or less. Older faucets that emit more than 2.5 gallons per minute are good candidates for replacement. Another option is to keep the old faucet, but get a new aerator or flow restrictor. This device will allow you to lower the flow rate without replacing the fixture.

Can You Install It Yourself?

Depending on your level of home improvement experience, installing low-flow plumbing could qualify as a do-it-yourself project. This is especially true when it comes to installing a new aerator on the end of an already-installed faucet. Most aerators meant to reduce the flow of water will fit in place of the old aerator without any changes. Removing the entire faucet or showerhead and replacing it with a more efficient model is not quite as simple, but it could still qualify as a DIY project for people with the right tools.

Two important things to remember when undertaking this kind of upgrade are: one, be very careful not to damage the threads on the existing pipe; and two, turn off the water and drain it from the pipe before removing the old showerhead or faucet. Low-flow toilets are more complicated because they require removing the water supply (tank) and bowl separately, and then resealing and re-attaching the proper tubing and outlet for the new toilet. This upgrade is best suited for a qualified contractor.

Financing Options Available

Luckily, some low-flow improvement projects, including high-efficiency showerheads and faucet fittings, faucet aerators, waterless urinals and low-flow toilets, often qualify for property assessed clean energy (PACE) financing. This means that a homeowner with equity in their property may finance the cost and installation of new low-flow equipment. The total PACE assessment is then added to and repaid through the property tax bill, rather than being attached to the individual.

With PACE, a property owner can pay for his or her project over the long-term, indirectly, by using the money saved in water and utility bills from the new low-flow plumbing. The PACE option makes it possible to invest in quality equipment to maximize water savings, and to have it installed – so that you are confident it is going to perform as expected.

Understanding Low-Flow Showerheads

The shower is the place where you will most likely notice changes when switching to low-flow fixtures.

The two main kinds of water-conserving showerheads feature different advantages and drawbacks:

  • Aerator showerheads: These mix air with water to create a fine spray. Quality aerating heads provide the same coverage as less efficient fixtures while using less water. The fine spray does create more moisture.
  • Laminar flow showerheads: These are shaped to create individual streams of water that are not mixed with air. This is the fixture of choice for people who want to lower the moisture and humidity caused by the shower.

What About Other Appliances That Use Water?

Dishwashers and washing machines also use water. There is no such thing as a low-flow washing machine or dishwasher, but energy efficient models do exist. Energy Star certified units are proven to save on electricity.

Homeowners can also lower water costs by taking a few simple steps, such as only running the dishwasher when it is entirely full, and setting the washing machine to the appropriate load level to eliminate excessive water use.

Are There Any Drawbacks To Low-Flow Plumbing?

Low-flow plumbing can save homeowners from high water bills, but these fixtures come with potential drawbacks. Quality low-flow products will usually perform as expected, but users must be certain that the products will not change their water use habits. For example, efficient toilets will sometimes not be able to flush all the waste at once. If it takes two flushes, this defeats the purpose of having a low-flow toilet in the first place. Some toilets address this specific problem by having two flush volumes; one for solid and one for liquid. The thing to remember with these models is to use the correct volume for your needs each flush.

Another potential issue is that low-flow toilets rely more on gravity than older models. In some homes, the pipes were installed with high-volume toilets in mind, and they are at the wrong angle for low-flow models. This is another reason that low-flow toilets might require multiple flushes. Low-flow showerheads and faucets are less prone to such problems, but you should beware of taking longer showers than you did before the new head was installed or using more water to wash the dishes. Low-flow showerheads may have weaker water pressure, so longer showers may result. The change in water pressure is less noticeable in kitchen and bathroom faucets with low-flow aerators.

WaterSense Products

The main question, of course, is how big the savings are. In the case of toilets, all American models now have a maximum required flow rate of 1.6 gallons per flush. Older models may use 3.4 to 4 gallons per flush. Therefore, if you need to replace the toilet anyway, any new model will offer savings compared to the older toilet.

The EPA claims that the best toilets use 1.28 gallons per flush. The organization has created the WaterSense label to mark the most efficient toilets. WaterSense showerheads, meanwhile, must use less than two gallons per minute, and bathroom faucets under 1.5 gallons per minute. Appliance performance (compared to standard models) is also part of the WaterSense product audit. Models that forgo too much water pressure to increase efficiency do not qualify for the designation.

Overall, installing low-flow plumbing is one of the easiest ways to save money on your monthly bills. You could start simply with a new aerator for your kitchen. Then, when the savings become evident, you can multiply them by adding low-flow units to the other faucets and showers and installing a new toilet. Together, these improvements can lower one of the home’s main utility bills.


PACE financing can help you retrofit your home to low-flow plumbing. Find out if PACE is available in your area – contact Ygrene at (855) 901-3999, info@ygreneworks.com.