American Standard FloWise Toilet

Toilet flushing accounts for up to 40% of water use in most residential buildings, making it the single largest water user. In turn, the opportunity for water savings from installing efficient toilets, and from toilet replacement, is significant. In addition to improvements to the traditional gravity system, pressure- and vacuum-assisted flushing systems have been developed that offer superior performance, albeit often with some increase in flushing noise.

GreenSpec refers to the EPA WaterSense High Efficiency Toilet (HET) specification, which applies to all types of residential toilets and encompasses the following aspects of performance:

1. 
   Flush volume – no more than 1.28 gallons per flush




2. 
   Flushing performance – minimum 350 grams per the Maximum Performance (MaP) test




3. 
   Fill valve – pilot valve type or equivalent performance




4. 
   Tank capacity – maximum holding volumes for tanks (with quantities determined by tank and flush type)




5. 
   Product marking – labeling and installation instructions that uphold the above criteria

Dual-flush toilets comply with WaterSense by making two flushes available: one for solid wastes and a lower-volume flush for liquids and paper. For dual-flush toilets, WaterSense factors water savings by averaging the high and low volume flush levels. Two reduced flushes and one full flush cannot average more than 1.28 gallons per flush.

GreenSpec users, however, should be aware of the limitations of the WaterSense criteria. MaP Test results many times higher than the 350 g minimum may come at the expense of other bowl-clearing aspects of performance, such as:

• 
  Floating or dissolved media clearance




• 
  Rim clearing




• 
  Water spot




• 
  Back wall clearance

To the extent possible, GreenSpec considers these other aspects of performance qualitatively (as GreenSpec users should as well) because no other publicly available standards are available.

GreenSpec lists toilets that are WaterSense listed and can flush 500 grams per MaP testing. Toilets that are included without WaterSense labeling are extremely low-water (ultra-efficient) use or have other unique green features.