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New or replacement toilets, aerators and showerheads are a great starting place for significant water savings; they are cost effective, and save water and utility costs. But as water costs continue to rise across the country, and some areas face droughts, aridification and water supply constraints, property owners — particularly owners of affordable housing — can benefit from additional water efficiency strategies.

1. Install weather-based smart irrigation systems.

Traditional irrigation systems rely on manual controls that can result in operators guessing how often to run the system, and lack leak detection or flow management — all of which can waste water and cause other issues, such as slip hazards and slope erosion.

Weather-based smart irrigation brings precision to the system, and can be fine-tuned to the soils and plants on the property. Flow sensors, master valves and app-based alerts enable problems to be detected and addressed quickly, minimizing waste and potential hazards.

AvalonBay is an example of a community that has implemented this technology. Phase 1 in 2014 included 29 separate communities with 127 controllers. The initial $750,000 investment was paid back within three years, with $494,000 in savings in 2020 alone. The company invested further in Phase 2 in 2021, with 315 controllers. The total investment of about $1.85 million is projected to save the company $831,000 per year.

2. Get rid of leaky toilets.

Building managers can get a sense from the water bill if there may be leaks in the building. But where are they? Toilets can be a significant source. Although fixing them may be relatively easy, it’s hard to know which ones need to be fixed, especially when you have hundreds of them under management.

Sensors were installed at MacArthur Park Tower, a high-rise senior housing facility in Los Angeles with about 200 units. Sensors can be placed on individual toilets — out of the way and small enough that residents likely won’t even notice. Connecting the sensor data in real time to the maintenance team’s work order system enables leaks to be identified and fixed quickly. This requires zero participation or behavior modification by residents, and can result in significant utility savings for building operations and increased repair efficiency.

In the first three days at MacArthur Park, the maintenance team learned that nearly half the water being used by toilets was due to stuck wide open leaks — i.e., once the toilet is flushed, it keeps flushing until it is fixed. In the first two months, toilet water usage dropped from 44% to 11% of total water usage, and it is still falling.

You can learn more about these and other water saving strategies for multifamily properties from the Department of Energy’s Better Buildings Initiative “What’s Next in Water Efficiency for Multifamily Housing” .

To stay current on the high-performance residential building sector, with tips on water efficiency, energy efficiency, indoor air quality, and other building science strategies, follow NAHB’s Sustainability and Green Building efforts on .