Mike Opitz PE, LEED AP
Certification Manager, LEED for Existing Buildings
U.S. Green Building Council
Introduction
With energy prices in the headlines lately, it’s all too easy to lose sight of a completely separate way for facilities managers to conserve resources and money: more efficient plumbing fixtures. For a long time potable water was considered almost too cheap to meter, or at least too cheap to investigate. Low utility rates for water supply and disposal did little to discourage wasteful water practices and technologies until the past 10-15 years. In response to rising rates in some jurisdictions, demand started growing for plumbing fixtures that did the same jobs with less water. Manufacturers responded to this demand, and many modern fixtures are truly high-performance: they deliver great service with much lower water use, and state of the art fixtures for some applications use no water at all!
If your building still has old (1990 or earlier) plumbing fixtures, you need to investigate retrofitting them with new technology. Depending on your local water rates, payback times may be quite rapid.
Water Efficiency: Technology to the Rescue
In most buildings plumbing fixtures provide essential services to occupants that themselves cannot be reduced: bathing, hand washing, and sewage conveyance. In all of these applications the water consumption depends on two basic variables: usage patterns and consumption per use. Usage patterns are largely a matter of personal preference, and building management can do little to change them. For the most part, lowering your water use in plumbing fixtures means improving your fixture technology to lower the consumption per use. For flow-type fixtures this means lowering the gallons per minute (GPM), and for flush-type fixtures, lowering the gallons per flush (GPF). This is water efficiency: getting the same or better service for less water by using better technology.
A Simple, Reliable, off-the-shelf Solution
Retrofitting the common flow fixtures in buildings – faucet aerators and showerheads – may be the easiest water-saving step you can take in an existing building: it’s as simple as unscrewing the old and screwing on the new, no change in valve required! Since the federal EPAct regulations of 1992 went into effect the conventional flow rate for both of these fixture types is 2.5 GPM. Super-efficient models can use as low as 0.5 GPM (faucets) and 1.5 GPM (showerheads) at full flow. The best new showerheads also allow you to control water flow rate separately from flow temperature via a separate shut-off valve near the showerhead. This allows water-conscious users to reduce water flow during soaping and scrubbing and use full flow only for rinsing, all without changing the flow temperature. A surprising number of users, once informed of this capability, will adopt this water-saving practice.
Retrofitting these flow-type fixtures is almost a no-brainer for any building. Although some occupants may complain initially because of different spray patterns, especially on showerheads, they eventually adjust. At the very least, try out the new fixtures in part of your building as an experiment. Consider tamper-resistant fixtures if suitable for your application. Finally, since flow fixtures use both hot and cold water, don’t forget to include the energy savings from reduced hot water consumption in your payback analysis.
Flush fixtures take a bit more work to retrofit but can save serious amounts of water and money. Fairly recently typical toilets used 3-5 gallons of water per flush and typical urinals used 2-3 gallons per flush. Early low-flush models from some manufacturers sacrificed performance to save water, which led to double-flushing, negating much of the potential savings, in turn causing a bad reputation in the industry. But those days are long gone. Since the appearance of lower flow standards in EPAct 1992, the technologies improved drastically and now most EPAct-compliant fixtures perform quite well. Conventional toilets now use 1.6 GPF, and conventional urinals use 1.0 GPF, far less than fixtures still in many existing buildings.
But don’t stop your flush analysis there. If you’ve decide to do a flush-fixture retrofit, or if the payback attractiveness looks only borderline, take a look at super-efficient toilets and urinals that beat the federal standard. A modern low-flow urinal uses only 0.5 GPF, and a low-flow toilet uses 1.1 GPF. Some new toilets are dual-flush models that use 0.8 GPF for liquid waste and 1.1 – 1.6 GPF for solid waste. These units will make your building even greener, and depending on pricing, may shorten your payback time as well.
Flush fixture retrofits tend to be direct bolt-on replacements, much like flow fixtures, just requiring more labor per fixture. One note of caution: when shopping for new plumbing fixtures, be sure to compare GPM or GPF at the same operating water pressure. Also keep in mind that actual performance and flow in your building will vary if your water pressure is different than the pressure used to rate the fixtures.
Cutting-edge Approaches
Market-leading “flush” fixtures actually use no water at all because you don’t flush them! Non-water urinals are a recent development, and work by using a specialized cartridge in the drain that allows waste fluid through while preventing odors from entering the room. They require no water supply and use standard sewage piping. The replaceable cartridges are good for a few thousand uses each, and this routine replacement cost must be included in the payback analysis, keeping in mind that it replaces routine maintenance/replacement on a conventional urinal’s flush valve. Cleaning practices are also different than water-using urinals, so some staff retraining may be necessary.
Composting toilets have been around for decades but have low market penetration because they’re so different from standard plumbing practice and they call up an image of the old-fashioned outhouse, with the attendant sanitary concerns. Modern systems are physically attractive and essentially odor-free, and well-designed systems provide easily-accessible compost and effective pest control. The downside is that they can’t use your existing sewage plumbing: dedicated waste infrastructure is required. This means they must be consciously designed into new buildings and are only suitable for existing buildings if you’re doing a significant renovation.
Conclusion
Installing water-efficient plumbing fixtures is a great way to green your building and improve your bottom line. The technology is reliable, affordable, and off-the-shelf, making it a low-risk investment that offers good financial returns.
Resources
U.S. Green Building Council (www.usgbc.org/leed)
The USGBC’s LEED for Existing Buildings program addresses water efficiency in several of its requirements and credits.
EPA water use efficiency program (www.epa.gov/owm/water-efficiency)
Articles, reference materials, and papers on all forms of water efficiency.
Water Wiser: the water efficiency clearinghouse (www.awwa.org/waterwiser)
Articles, reference materials, and papers on all forms of water efficiency.
Industrial & Commercial Building Water Conservation (www.p2pays.org/water/tech.asp)
Fact sheets, checklists, and technical guidance from North Carolina state government agencies.
