NeutralAxis

For one of my commercial clients, I’ve been looking at ways to save water, and thus money.  The figures for water savings are eye opening.

The setting is a national restaurant franchise that typically seats around 180.  In the men’s and women’s restrooms are a total of typically 3 water closets, 1 urinal, and 2 lavatories.  I made a few assumptions on use, starting with their estimate of around 500 customers per day.  I assumed a 50/50 male/female mix, with 70% using the restroom during their visit.  For men I assumed an 85/15 split for urinal/water closet use.  Hand washing at lavatories was estimated at 15 seconds per use.

• Switching to water closets that flush using 1.28 gallons per flush (gpf) instead of 1.6 gpf saves 23,500 gallons per year.
• Switching to urinals that use 1 pint per flush instead of 1 gpf saves nearly 52,600 gallons per year.
• Switching to lavatory faucets that use 0.5 gallon per minute aerators instead of 2.2 gpm saves 54,300 gallons per year.
• Combination of all three measures saves over 130,000 gallons per year.

Waterless urinals are becoming more common and would save another 7,000 gallons per year, but they require more care from the cleaning staff to stay odor free.  I’m not sure I want to risk using them yet in a restaurant setting.

Here’s the fly in the ointment.  Water in the area where we do these projects is cheap at around $3.75 per 1000 gallons, so annual savings is in the vicinity of only $500.  So how much would those measures cost to implement and how long would be the payback period?  That’s still to be determined.

I think deciding to implement these changes is going to boil down to whether the client has any interest in promoting good environmental stewardship rather than a simple matter of money.

Sloan 1/8gpf urinal
Sloan 1.28gpf flush valve
Sloan water-free urinal