28 Jul 2009

Bleg: Water Audit Calculator

BO wants your help:
I created a self water audit calculator [XLS] that I'm considering putting on our website once I have it tested and developed a bit further.

I'm wondering if you would be willing to test this calculator for your own water use at your home. All you need is your last water bill and some basic information about your household water use.

It would be great if you can tell me if this calculator reasonably estimates your water use, and whether you think this type of thing is useful.

The idea is that a customer would be able to better understand how water is being used in the home and why a water bill may be high,etc.

They would be able to determine their gallons per capita per day and we could then assign a relative rating to this number.

I realize that some of the information on the calculator may be too complicated for the average customer to use. For example, many people don't know how many zones they have on their irrigation system or the flow rate of a particular sprinkler. An alternative method to gathering this info would be to have an option where people estimate the amount of irrigated area (square feet) and apply some one-size-fits-all water demand for this area. This method which I would not prefer, would not be nearly as accurate but would be easier for the customer to input.
Bottom Line: It's hard to know what your water use is and then match that to your bill. That's what these calculators are for. Please give Ben some feedback -- email linked to his name above or comment here -- so he can make a good one!


  1. I played with it a bit. Looks good.

    My only concern was also mentioned by David - getting your estimates to match up with your billed consumption is likely going to be very tricky for most users.

    That might actually cause some folks some concern and think that perhaps they have a leak, or the bill itself is wrong. That concern could translate into many calls to your customer service/billing department.

    In an attempt to try and preclude a flood of calls I would provide some more explanatory info on the sheet in big bold print telling folks not to worry if they can't get their numbers to match the actual billed gallons per person/day.

    As you said the irrigation stuff is likely to be problematic. I would try to simplify the irrigation calcs by just asking for the quantity of each emitter type (drip, sprinkler, etc.) and have the user just enter the estimated number of minutes the system runs and the number of times per week it runs.

    Also, you might want to add a cell up near J8 that sums their estimated usage in L29 and L53.

  2. thanks for that feedback. Others, please try it out and let me know your comments/suggestions. I'll be working on making some revisions and hopefully post an updated version in a week or so. thank you,

  3. Based on my household experience you may have missed some significant uses (at least compared to some you do list)...

    Dishwashing is more than just what the dishwasher uses...precleaning (yes even for our brand new high efficiency dishwasher ($1K)) is required, and some pots and pans we do by hand. For a typical evening cleanup this involves approx. 5 minutes of faucet run time. Mopping and other indoor cleanup for us (4 persons + dog) is probably in the 20-100 gal/wk range too. Good you have # flushes, as opposed to toilet trips. Also you may wish to footnote one should count all active shower heads (if they have a spa like shower).

    Outdoors there is typically more than just irrigation. Obvious is a pool/spa or other water feature(which if used by kids has quite a splash loss....otherwise monthly average net evap, with an area input may estimate top-off useage. Also, all other outside useage...washing dog/cars/deck/kids (at my house this offsets sprinkler use somewhat). And, any cooling use ie, evaporative coolers and/or mist systems.

    Your talley may help users understand the relative amounts different household uses are responsible for. As far as matching a meter reading, even with all uses carefully accounted for.. a new meter can be off 5% (although the error is to usually undercount useage). Just the rounding error of +/- 1 unit/month can translate into 10's gallons/day error on the household use.


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