UPDATE: In October 2022, we installed a Flume courtesy of the LADWP rebate program. This device provides more detailed water usage and data. Using this data, I've made corrections to my estimates below in red.
In February of 2020, my husband and I welcomed a new tenant into our home. However, after just a month or two, we realized that our utilities, specifically our electricity and water usage, doubled. What was going on? The new tenant was a single person - could they really double our utilities?
In September 2021, the tenant spent an unprecedented week outside of the house. This gave us the perfect opportunity to measure our typical usage and understand our each member of the household's impact.
Methodology
I identified our primary areas of water usage:
Landscaping
Dishwasher
Washing machine
Shower
Sinks and toilets
I would take a meter reading at the start and end of my week long audit to estimate our total usage, but how would I figure out how much water each of these areas used?
Fortunately, we have a Rachio smart irrigation system, so I already had all the data I needed for the landscaping. The dishwasher, washing machine, and shower are all run somewhat infrequently with defined start and stop times, so I decided to do a meter reading before and after each use to calculate their usage. I was less interested in the sink and toilet usage, so I decided to assign whatever was left over from the total usage to this category.
Results
Total Usage: 254.5 gal
Landscaping: 78 gal
Shower: 45 gal (15 gal per 10 min shower) (Accurate - 1.5 gal/m flow rate)
Dishwasher: 15 gal (7.5 gal per run) (Underestimated - approx. 11 gal per run, 22 gal total)
Washing machine: 37.5 gal (per run) (Accurate)
Sinks and toilets: 79 gal (Per dishwasher update, 72 gal)
Adjustments
This was a particularly busy week for us, which meant more takeout and tolerance for funky hair than usual. I wanted this to represent a "typical" week, so I made some adjustments.
I added 2 more showers (30 gal), another dishwasher run (7.5 gal) (11 gal), and a quarter of a washing machine run (9.25 gal) to account for the monthly occasion we run two loads of laundry instead of one for the week.
That brings our "typical" weekly usage for my husband and me to 286 gal (289.5 gal), or 20.5 gal (20.67 gal) per person per day. If we remove irrigation (since it varies widely based on the weather and what we have planted in the garden at the moment), our in-home weekly usage is 208 gal (211.5 gal) or just shy of 15 gal per person per day.
Comparison
According to the EPA, in 2015, the average American uses 82 gallons of water at home per day and according to the California State Water Resources Control Board, the average Los Angeles County residents used 83 gallons of water per day in 2020 and 2021. That puts our usage (including irrigation) at just 25% of that of the average American.
What about the tenant?
For our July-August billing cycle, LADWP determined our home consumed 8 HCF (hundred cubic feet) of water, or approximately 5984 gallons. According to our Rachio, our landscaping took about 1300 gallons of water in that time. 8 weeks of our typical in-home usage is another 1665 gallons (1692 gal). That means that our tenant used over 3000 gallons of water, or approximately half of our household's total usage. However, over a two month period, that puts our tenant at about 50 gallons a day, or 36% less than the average American and Angeleno.
Conclusion
I don't feel particularly deprived with our water usage. But I also realize that not everyone would tolerate my brown grass or turn off the shower while they soap up. Will the average person reach our level? Likely not. If you asked my tenant about their water usage, they likely believe their usage is the same as ours or that our conservation efforts are extreme.
And it got me thinking about our water strategy in general. In California, we're in a drought. Despite that, Los Angeles County's water usage is on par with the national average. Xeriscaping is growing in popularity, but pools, lawns, and car washes are all too common.
Los Angeles needs to get smarter about its water. I would love for everyone to voluntarily rip out their sod, shorten their showers, and skip the car washes, but it's not a realistic strategy to focus on. We need sweeping structural changes, from the proposed sewage treatment efforts to stormwater systems that send our rain to reservoirs instead of the ocean to a structured water plan that ensures water is allocated fairly and sanely.
First Written 9/18/2021, Last Updated 10/21/2022
Flume Updates
We installed the Flume in mid-October 2022, which recommended a household "budget" of 16,900 gallons per month. Our first full month of data showed we used 2,560 gallons for a household of three adults, or just 15% of our recommended budget and an average of 27.5 gallons of water per person per day.