Water Systems

Water Systems

Water Systems

While utilities and agriculture are the source of the majority of water consumption in the US, buildings and associated landscaping have a significant impact on a facility's environmental footprint. See also our Site and Lanscape page for more information on stormwater retention and irrigation opportunities.

Flush and Flow Fixtures

Flush and flow fixtures are some of the easiest improvements that can be made in a facility. When considering fixtures, it's critical to consider the overall performance, not just the flow rate. As a result, we recommend purchase fixtures that have received the EPA WaterSense label, particularly for toilets, as they are third-party tested for both flow-rate and performance.

Toilets - Consumer Reports has a concise buying guide that describes the different types of residential toilets mentioned below.

  • For residential, tank-style toilets, we recommend purchasing a complete low-flow toilet, as the flush performance is driven by not just the bowl design, but how the bowl is connected to the tank. There are now many 1.28 gallon per flush (GPF) toilets that have as good or stronger flush performance than older, higher consumption models.  
  • It's possible to get tank-style toilets with a lower than 1.28 GPF ratings, but these often require pressure assist systems that make a loud "WHOOOSH" sound when the toilet flushes.
  • Retrofit kits that reuse the existing, higher-flow tanks and bowls may have performance issues, though they often the least expensive option for reducing water consumption for toilets. 
  • From a cost perspective, many models of low-flow toilets are nearly identical in price to the higher flow models, and are always recommended in new construction projects.  At the same time, water costs are relatively low in the US, and retrofits of otherwise functioning toilets with low-flow systems may have long payback periods.  


  • Faucet aerators are one of the least expensive and DIY friendly retrofits available.  Often costing $5 or less, it's possible to retrofit almost any model of faucet with a 0.5 - 1.5 gallon per minute (GPM) aerator.  Before ordering, make sure you know whether the existing faucet is a 'male' or 'female' threaded and the size.
  • Consider the use of the faucet before selecting the flow rate.  A bathroom sink where people are only washing hands or brushing teeth will likely be fine with a 0.5 gpm or less aerator, but this could be frustrating in a kitchen sink where people are routinely filling pots (i.e. to fill a 2-gallon pot would take four minutes!).  As a general rule, 1.5 gpm should be the highest flowrate for kitchen sinks or similar uses, and 0.5 gpm will be fine for bathroom sinks. for faucets that are used exclusively to fill pots and buckets (e.g. a janitors closet sink), no flow restriction may be desired.  
  • Since faucets frequently use hot water, these can drive savings not only in water use but also natural gas or electricity used to heat the water.  Payback for low-flow faucets in both new construction and retrofit scenarios are generally very fast.  


  • Certain low-flow showerheads (defined as 1.5 GPM or lower) maintain a strong spray and high-pressure feel.  While different manufacturers have different names for it, find a showerhead that uses nozzle shape or mini-turbines to provide a higher pressure spray as opposed to one that aerates the stream and results in a feeling of less pressure to reduce potential complaints.  
  • Similar to faucet aerators, the hot water reductions typically yield large savings in both new construction and retrofit scenarios which result in fast payback periods.