If you will be using graywater, rainwater, or treated wastewater, you’ll need dual plumbing for interior water fixtures. Communicate this need to your civil and plumbing engineers. You should also discuss any location and structural issues if your project is going to have a rainwater cistern—sometimes they take up more space than anticipated.

Untreated rainwater and graywater may corrode plumbing systems or lead to biological growth. You should plan for water treatment and filtration, or use corrosion-resistant materials. All graywater plumbing and storage must be separate from regular sewage plumbing.

If needed, size graywater and rainwater systems to satisfy the credit requirements. Sizing these systems can be more complicated than you might initially think. It’s best to involve a civil engineer or someone familiar with these systems. 

Review your water balance study and determine what water reuse would be most appropriate for your project. If you have gym showers, it might be best to treat and reuse graywater from laundry or shower facilities. If the building is located in a rainy climate, you can capture and reuse rainwater.

Review your water balance study and determine what water reuse would be most appropriate for your project. If the building is residential or a hotel, it might be best to treat and reuse graywater from laundry or shower facilities. If the building is located in a rainy climate, you can capture and reuse rainwater. 

If you cannot meet the credit through the use of fixtures alone, determine how much non-potable water you need to use in order to comply. 

Typically, a dual-flush toilet—with the heavy-flow at 1.6 GPF and low-flow at 0.8 GPF—does not meet the credit requirements. However, a 1.0 GPF ultra-low-flow toilet or a 1.28/0.8 GPF dual-flush toilet—in conjunction with waterless or pint urinals—will meet the credit requirements, and you can avoid using non-potable water. For occupancies that do not use urinals, such as pre-kindergarten or elementary schools, you may not be able to meet this credit through the use of fixtures alone and you’ll find that you have to include water reuse in your water reduction stragey. 

Typically, a dual-flush toilet—with the heavy-flow at 1.6 GPF and low-flow at 0.8 GPF—does not meet the credit requirements. However, a 1.0 GPF ultra-low-flow toilet or a 1.28/0.8 GPF dual-flush toilet—in conjunction with waterless or pint urinals—will meet the credit requirements, and you can avoid using non-potable water. For occupancies that do not use urinals, such as residences or hotels, you will not be able to meet this credit through the use of fixtures alone and you’ll find that you have to include non-potable water reuse in your water reduction strategy.

Track and record information on applicable fixtures, including the manufacturer, model number, and flush or flow rate. This will help you when filling out the LEED Online credit forms. Fill out the LEED Online form early in design simply as a draft to determine if you are meeting the requirement. 

Remember that this credit is based on EPAct 1992 and subsequent rulings of EPAct 2005, the 2006 Uniform Plumbing Code, and the International Plumbing Code. The baseline case for this credit includes these standards: