10 May The One-Day-a-Week Solution to Austin’s Summer Water Use

Austin residents can water lawns two days per week from May through September, under water conservation measures approved in 2007. Odd numbered houses have two designated days (Wednesday and Saturday), even numbered houses have two other designated days (Thursday and Sunday). Businesses and apartments have Tuesday and Friday.

This scheduled simplifies and improves what was once a scatter-shot of changing days based on the last number of one’s address. Under the old schedule, there was no set schedule: your watering day changed from week to week.

Now, the entire side of a street should water on the same day, making it easier to follow along and notice when someone is watering on the wrong day.

Austinites have responded very favorably to the twice a week schedule. No one is supposed to water on Mondays, and water use on Mondays the last two summers has been 25-35 million gallons a day less than Tuesday through Sunday.

Further, in 2008 and 2009 our “peak” water use – the highest amount of water used in one single day remained 12 million gallons a day less than our historic peak of water use, back in 2001.

Peak summer water use is what drives the supposed need for Water Treatment Plant 4. Lowering peak water use therefore reduces any perceived pressure to expand water treatment capacity. It is obvious that the City should investigate opportunities to lower peak water use to save rate-payers the enormous cost on Water Treatment Plant 4, which is $1.2 BILLION including interest on borrowed money.

The water conservation measures of 2007 call for reducing lawn watering to ONE day per week when one of two things happens: the total combined storage of lakes Travis and Buchanan falls below 900,000 acre-feet or water use tops 260 million gallons a day (MGD) for three straight days or 270 MGD in one day. During two summers of drought – when you would expect lawn watering to be highest – we haven’t come within 40 MGD of the 270 MGD threshold. And if we adopt a once-a-week watering schedule in the summer, we will further reduce our peak summer water use.

During the devastating drought of 2008 and 2009, water inflows to lakes Travis and Buchanan literally dried up, and their combined storage dropped below the City’s threshold, and the City implemented “Stage 2″ drought restrictions – including one day per week watering – in late August of 2009.

The result? According to the Austin Water Utility – the same people pushing Water Treatment Plant as necessary and essential to providing Austin with water in 2014 – water use dropped 20% before rains came, reducing lawn watering.

During summer, water use is usually around 200 million gallons a day if it’s not raining. 20% of 200 MGD is 40 MGD. Guess what the treatment capacity of Water Treatment Plant 4 would be if it opens? 50 MGD. So by simply adopting a once a week watering schedule, we can save the equivalent of 80% of Water Treatment Plant 4’s capacity. But instead of costing ratepayers $1.2 BILLION, it would cost hardly anything, save for some advertising and enforcement.

– Colin Clark