Plumbing – water conservation

It’s time to switch gears from the DWV system to fresh water plumbing.

I didn’t expect that there was much to the plumbing system. A cold water and hot water line to every fixture. Done.

Well, I was encouraged to reconsider while preparing for a presentation at Greenbuild 2010 here in Chicago. My co-presenter, Gary Klein, covered the subject of efficient plumbing systems. He lives and breathes high performance hot water systems and is delightfully obsessed with their efficiencies.

We began talking – about three weeks before the basement plumbing installation. And boy am I glad that we got to talking! Here is what I took home.

The objective…

… of the fresh water plumbing system should be resource conservation.These are the three key points of resource conservation:

  1. Water conservation
  2. Material conservation
  3. Energy conservation

Let’s take a look at each item, starting with…

… Water conservation

To reduce the overall consumption of water throughout the house, we had planned on a variety of low flow fixtures. The use of low flow fixtures was by choice, but was also mandated through a plumbing code variance as I had mentioned in a past post.

Here again is a summary of our targeted low flow rates for all fixtures:

  • Toilet 1.28/0.8 gpf
  • Bathroom faucet 0.5 gpm
  • Shower 1.5 gpm
  • Kitchen 1.5 gpm

Water Sense

A helpful guide in water conservation is the US EPA Water Sense program. It establishes minimum performance requirements (i.e. reduced water usage) for toilets, showerheads and faucets amongst other fixtures. The Water Sense web site has a product search function that will list qualified products and their low flow rates.

You may have seen the Water Sense labels on toilets or faucets in your plumbing supply store. It is now relatively easy to find fixtures that actually exceed the Water Sense requirements.

Not part of the Water Sense program are laundry machines and dish washers, although they are big water consumers. Both appliances are, however, part of the Energy Star program. Still, it is worthwhile to look out for their water consumption.

Washing machines

Front loading washing machines can clean more clothes with less water by design. Whereas top loading washers need to fill with water until all clothes are submerged, front loading, or H-axis washers rotate the clothes through water in the lower portion of the drum, thus cleaning more with less.

The average water consumption for washing machine in the U.S. is 41 gallons per load. High efficiency machines use as little at 28 gallons per load. That is still a lot of water, though.

We decided for an Energy Star rated front loading washer, which according to the Energy Star specifications uses only 11.4 gallons per washing cycle and has a water factor of 3.3.


We haven’t purchased a dishwasher yet and  are still cleaning the dishes by hand. This, ironically, leads to more water consumption than with a dishwasher, according to Energy Star data. The listed savings though only apply to Energy Star qualified dishwashers.

Some of those use less than 2 gallons of water per cycle, which can add up to quite some water savings, considering that conventional or older dishwashers use over 6 gallons per cycle. Our target is to find used dishwashers with a water consumption of 2.5 to 5.5 gallons/cycle.


Last but not least, the recycling of greywater, which I covered in a recent post, is another water conservation strategy.

About Marcus de la fleur

Marcus is a Registered Landscape Architect with a horticultural degree from the School of Horticulture at the Royal Botanic Gardens, Kew, and a Masters in Landscape Architecture from the University of Sheffield, UK. He developed a landscape based sustainable pilot project at 168 Elm Ave. in 2002, and has expanded his skill set to building science. Starting in 2009, Marcus applied the newly acquired expertise to the deep energy retrofit of his 100+ year old home in Chicago.

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.