A couple weeks ago I finally finished the tallying of my summer 2013 water audit. Unlike my trash and energy audits where I have a good baseline from doing these audits since 2001, I have no baseline and no good methodology for a water audit. Until we moved into this house in 2010 I had never lived (as an adult) in a place where I got a water bill, and from 2010 through late 2012 those bills were bimonthly. It’s nearly impossible to use a bimonthly bill to get any sense of your water usage since you end up with summer watering mixed in with cooler months. In the past for my water audits I’ve timed how long showers last, how long it takes to wash my hands, etc. in an attempt to measure my water use. This time I decided to measure my outdoor water use since it’s all through hoses, and then just do the math for indoor use based on my bill. So I got little flow meters for both hoses, and started recording. Unfortunately I did not do a calibration check on either meter and one of them conked out before the end of the month. When I tallied up the amount I had supposedly used in my outdoor watering during the month, it was more than the total water usage in my bill.

Without having a way to calculate indoor vs. outdoor water usage, I’m still having to do this audit based on a lot of estimated numbers and various assumptions. The final tally gave my top 5 water uses as 1-watering trees, 2-showers, 3-toilets, 4-watering lawn, 5-watering potted plants. Assuming that I can use proportioning between the two water meters that were on the hoses, I was using SEVEN times more water on the trees than the lawn.

Now, I’m stingy when it comes to lawns. I don’t water during the winter (rainy season here in Sacramento), and I only water once per week in the summer. Plus we have a small front lawn and don’t water the little backyard patch-o-grass at all. But we have a couple trees in the front yard that are still young and getting established, and a quasi-orchard in the backyard (established nectarine, new apple, new pomegranate, established persimmon, established pear, established orange, established pumelo). But I was “deep watering” the trees by watering monthly and letting the hose water run slowly at the base of each tree for a while. And sometimes would forget to move the hose in a timely manner. They all started producing fruit only after I started watering them, so it is important to me to water them well, but since trees are on an annual cycle there’s no easy way to be sure that if I reduce water by x amount they will still fruit nicely.

I tried looking for suggestions of how much water to apply to fruit trees online, and didn’t get much help. Most of what I found I’m assuming is for commercial growers since it was talking about daily watering. When I did the math those suggestions weren’t far off from what I was applying monthly. I take that to mean I’m overwatering since you have to account for how much the soil can store so I may be applying as much water as the tree needs in a month but since I was doing it all at once much of that water would have been lost as excess.

For the end of last summer I switched to weekly watering for around 5-15 minutes depending on the size of the tree instead of monthly for 1 hr each. But this year with the drought and push to conserve water I’m wondering how to proceed appropriately with these fruit trees, and don’t yet have a plan that I can really feel comfortable with.