Utilities Reduction Project Part III: Water & Sewer

It is time for the next installment in my utilities reduction series. I completed the last of my major water reduction projects a month ago and have a good measurement of my new baseline. The old baseline taken last winter was ~7.7 ccf/month (5,760 gal/month) or 47.3 gal/day per person. This is still half of what the EPA and many states regard as normal use, so I knew this would be a challenge. Our new measured baseline is almost exactly 4.0 ccf/month (3,000 gal/month) or 25 gal/day per person. Net reduction is 48%, 44.4 ccf or 33,200 gal/year.


The major reductions in water use were:

• Front loading washer: This was the biggest single factor, saving roughly 920 gal/month or 0.69 ccf/month.
• Ultra low flow showerheads: All three showers now use 1.5 gpm High Sierra or 1.6 gpm Roadrunner showerheads rather than the standard 2.5 gpm nominal units. This is worth about 550 gal/month or 0.41 ccf/month.
• High efficiency toilets: I replaced the poor performing and one high flow toilets in the home with Toto EcoDrakes. This cut the flush water use by roughly 910 gal/month or 0.68 ccf/month. The need for multiple flushes has been eliminated as well so the actual reduction is probably greater.

The above only account for half of the total reduction. There have been other small habit changes that have also contributed, plus some minor related projects such as:


1. Reduced water pressure from ~75 psig to 50 psig., (replaced failing PRV and added a thermal expansion tank.)
2. Insulated hot water lines to shorten warm up draws.
3. Piggybacking/combining uses in the kitchen to eliminate long warm up draws.
4. Going to quick cold rinses (rather than hot) to remove food remnants before putting items in dishwasher.
5. Other small changes/general awareness of water use.

The new water usage rate puts us on a par with or below the previous owners’ total monthly indoor use, except there are four of us and there were two of them.

With regards to outdoor use we use minimal amounts to water the grass to keep it alive during dry spells. This summer was wet so we used about 3,000 gallons (4 ccf) for irrigation the whole summer. I anticipate it being about 9,000 gallons (12 ccf) for average summers. The previous owners used nearly 200 ccf (150,000 gallons) for irrigation during the hot summer before we moved in.

All told I project our indoor and outdoor water use will be 60 ccf/year (~45 kgal/yr). In our previous home we had an old 5 gpm showerhead, older dishwasher, and our old clothes washer, plus modified high flow toilets, but no sprinkler system. There we used about 113 ccf/yr (85 kgal/yr).

Our current water use is roughly that of the per capita use in China. At our current incremental charge rate for water and sewer the utility savings is about $176/year. (This does not include water heating demand reduction.)

 

I do for some things. I've considered it for others, but decided against it for several reasons (perhaps applicable only to us):
1. We rinse right after the meal to get things off of the plate. Cheese stuck to a plate all night typically won't come off in the dishwasher. Potatoes, rice, and beans stuck in pans tend to leave something behind. Since we rarely do more than a single load per day that means a lot of time for stuff to dry in place between loads. Of course this varies depending on when the washer is full.
2. Wash cycles take forever and use more hot water if there is more food in the machine.
3. As in the case of plates, we soak or rinse pots and pans. If you get water on it right away and let the thick stuff sit it comes off easily.
4. The water to the dishwasher needs to be hot to be efficient, so we have to pull about 4-6 quarts anyway immediately before starting it. (It's the longest plumbing run in the house and most of it is uninsulated behind drywall.) We put that cooled water in the line to good use rinsing things that need it.
5. My experiences on older dishwashers was that various solid food remnants ended up stuck to glasses if left on plates...so I like the dishes to be free of refried beans and the like before they go into the machine.

We don't rinse glasses, and not much for silverware. Bowls maybe half the time, depending on what is in them. Plates might not need rinsed either depending on what was on them.

Nothing takes a second trip through the dishwasher. Things that once routinely did no longer go in and are hand washed. Plus wooden handled items, stemware, and the nonstick we always handwash.

 

With earlier less efficient and poorer performing dishwashers, I preferred to handwash everything. I ridiculed dishwashers for two decades. But I've measured and can't really beat the efficiency of this newer machine, even with quick pre-rinses. I already did the same thing for hand washes...so there was no net difference in the pre-wash step.

Since I'm using cold spray for quick rinses of dishes that could benefit, I'm not losing much at present. That spent to remove the cold dead volume to get hot water for the machine is not wasted. (This is analagous to combining trips in the car.)

I should have added intially that I only run full loads. I'm pretty efficient at packing the dishwasher and still getting 100% of the items clean. My wife, bless her heart, can't fit nearly as much in as I can...and in the past has had trouble with parts of the load not getting clean.

 

Just a run of the mill Energy Star Whirlpool. The name on it is "Quiet Partner I" although it is not that quiet... I didn't select it; it was here (new) when be bought the house.

Our results are certainly beatable. Those who only flush for #2, bathe less frequently, use gray water etc. could probably cut per capita use by half again.