Measuring Up

I’m doing something a bit different this week. With all of the recent talk about the drought, I’ve been giving a great deal of thought to how we use water and what we as individuals can and should be doing about it. To date 2015 is shaping up to be the hottest year in recorded history, and regardless of whether or not you think humans have anything to do with it, the fact of the matter is that global climate change is real, and we need to adapt to it. One consequence of climate change appears to be a very real change in our weather patterns: the “new normal” here in California looks to be a lot drier. While there may well be years where we get more rain and snow, I think we should act as if the last couple of years’ weather is what we’ll continue see in the future. We likely won’t be able to count on a significant Sierra snowpack, which historically has been responsible for about one-third of the water we use throughout the year. Thus, we need to improve how we capture and retain what rainfall we get, and we need to use what we get much more efficiently.

While I as an individual can’t build a dam or a water pipeline from the Pacific Northwest, I can do something about capturing and retaining water: I can (and plan to) install rain barrels around our yard, fed from our downspouts. But what I really wanted to discuss today is how I’ve been measuring our water usage, and what I’ve learned in the process.

To begin with, I took a look at how much our household has been using. The water bills we get from Redwood City are a great place to find this information. They list our usage (of course) along with a “Voluntary Water Target” that the city hopes we will achieve. With all this talk about percentage cutbacks—25% from the governor, and different figures from the county and city—I’ve been confused about just what this all means for me, and what amount we are supposed to cut back from. Fortunately, Redwood City aims to cut through the confusion: rather than having to do any calculations ourselves, if we just stay at or below the target printed on our bills we’ll be conserving the needed amount. Since that target is one that is both individualized for each household and adjusted for each season, this is a task that should be very doable.

Rather than digging out old water bills and looking at the targets and usages there, though, I strongly recommend checking out Redwood City’s My Water website. You don’t have to set up an account: to log in you only need the account holder’s exact name and the six-digit account number, both of which can be found on a recent water bill. On the My Water site you can specify the factors from which your water target is calculated—such as number of residents in your household, amount of turf and other landscaping, etc.—plus you can easily see your past year’s water budget (the Voluntary Water Target) and usage in a nice graphical form:


While getting and staying below the budget is a good start, I don’t believe we should stop at that. Given the uncertanties we face about future water supplies, I feel we should be doing all we can to save as much as we can, regardless of the calculated budget. Redwood City itself is doing its part, both by reducing water use by parks and city facilities and by increasing the use of recycled water in places where potable water isn’t absolutely necessary. As for us residents, we’ve all seen the standard tips for reducing water use, such as checking for leaks, cutting back on landscape watering, taking shorter showers, flushing less often, and so on, and hopefully we are all doing at least that. For those of us looking to do more, the city has a page on its website devoted to water conservation that lists several rebate programs for things such as replacing lawns with “water efficient” plants, purchasing rain barrels, etc.

My wife and I have already moved to the “bucket in the shower” phase: to the benefit of our outdoor potted plants we bought these two 6-gallon water buckets from Home Depot and use them to capture the warm-up water from our shower:


In comparing our usage to our targets it’s clear that my household is doing pretty well. However, I couldn’t help but wonder just how much “bang for the buck” were we getting from our various efforts. As an engineer, I realized that what I needed was data. In particular, I wanted to know just how much water each activity consumes. Measuring the amount of water used during a shower is easy enough, given buckets like those shown above; simply capture all of the water from the shower head for a known period of time, measure how much water you captured, and divide the amount of water, in gallons, by the time, in minutes, to get a gallon-per-minute figure. Then you’ll know how much water a five-minute shower consumes as compared to a ten-minute one. As for the toilet, I’m assuming that the figure printed on the toilet itself is reasonably accurate, so (in our case) skipping a flush saves 1.6 gallons. But what about other water uses? In particular, how much water do our clothes washer and dishwasher use, and just how much water do we use when irrigating the yard, anyway? By determining those numbers, I’d then be able to determine how other lifestyle changes would affect our daily water use, and would know which efforts would prove to be the most effective.

I could find no record, either in the manual or on the web, of how much water our washing machine is supposed to use. And while our dishwasher’s manual does have usage numbers, it lists a range: somewhere between 1.5 and 4.5 gallons for a regular cycle. Clearly, I needed a way to measure our actual water use with reasonable precision. And then I realized that we all (well, maybe not those of you in apartments) have exactly the tool we need to do so: our water meter. You know, that meter that most of us have never actually seen? It turns out that although your bill is based on “units”—each of which is 748 gallons, or 100 cubic feet—your meter is significantly more accurate than that, and can give you readings down to one-tenth of a gallon or even less. Simply by taking “before” and “after” readings, and by being careful not to use any other sources of water while you are taking your measurements, you can get some really useful information about just how your household uses its allotment of water. Personally, I had a lot of fun doing it myself, but if you have a child living at home of an appropriate age, I could envision assigning this chore to them: they might really enjoy the process (and perhaps even get a good Science Fair project out of it!).

So just how do you read your meter? It’s actually pretty easy. First, you need to locate it. You’ll find it somewhere between your main shutoff (you do know where the shutoff is, don’t you?) and the street. Generally, it’ll be close to the street, to make the meter-reader’s job easier. In our case, it is located in the parking strip in front of our house, in an appropriately labeled box:


To lift the lid simply stick a screwdriver or some such in the rectangular hole, angle it, and lift. Note that you may need to clean the dirt off the lid first, and you may have difficulty the first time you open it due to accumulated dirt between the lid and the box. (Once open, clean the lip on which the lid sits to make subsequent opening easier.) Be a bit careful if your lid has a black circular thing on it, like this:


That black thing is an antenna, used by a so-called “smart” water meter to transmit its readings directly to the water company. Below it, on the underside of the lid, is a black box with a wire connecting to the meter. Be careful not to damage this box or the wire.

According to our Public Works department, of the 24,000 or so water meters in the City of Redwood City, about 15,000 of them have been changed over to smart meters. Smart meters don’t require a person to come out and read your meter: they send their readings electronically to the water utility. If you don’t have one, don’t fret: the city should get to you eventually. When? It’s hard to say. I’m told that they are replacing them in phases, looking at meter-reading routes and giving priority to hard-to-read locations and high water users. Regardless of which type you have, however, you’ll still want to learn to locate and read your meter yourself, as I’ll explain shortly.

If you don’t have a smart meter, when you open the lid you’ll see something that looks like an old pocket watch (here, I’ve cleaned out some of the accumulated dirt in the box, and flipped open the meter’s lid):


[I’m now going to tell you how to read your meter. If you don’t care for the details, skip ahead a couple of paragraphs to find out what I learned from reading mine.]

The odometer-like readout indicates a number of whole cubic feet, while the red hand on the dial indicates a fractional value: the tick marks around the face of the dial each represent 1/100 of a cubic foot. When reading this type of meter, it is important to note that the rightmost digit on the “odometer” advances smoothly as the dial’s hand rotates. Thus, when the pointer is pointing straight down (to 5/10), the digit will have advanced halfway to the next. And when it is pointing to a higher number, such as 9/10, the rightmost digit will have advanced nearly all the way to the next position. Thus, be careful to note that when the indicator shows more than 5/10, you will need to subtract one from the digital value shown. As for the different digit colors, those are just to make things simpler for the meter reader: since we are billed in 100-cubic-foot “units” (1 unit being 748 gallons), the meter reader just notes the first three numerals (black digits on a white background; “460″ in the above picture). For measurement purposes, though, we need to care about the full reading, which in the above photo is 46038.25 cubic feet.

Taking a reading is even simpler if you have a smart meter, since they present their values entirely through a digital LCD display. Like this:


Here, the readout is presented as 1/1000 of a cubic foot: look closely and you’ll see a decimal point between the 5 and the 4 in the above picture. The digits with the lines above them (000005, or the whole number of cubic feet, in the above photo) are what is reported to the water company. Flow is indicated not by a black spinning triangle, but a “+” within a circle in the lower part of the display (water was not flowing when I took the above picture, and thus the flow indicator isn’t showing). A smart meter periodically transmits its results (once an hour, I believe); since you don’t have control over when it does so, relying on the online readings for precise measurement may be much harder (and less accurate, since the fractional digits aren’t transmitted) than actually reading the meter yourself. Thus, regardless of your meter type, reading your own meter is the best way to measure smaller amounts of water use.

Whether your meter is smart or not, to measure water use you don’t care about the absolute reading but instead care about the difference between two readings. So, for instance, to measure the amount of water used by your dishwasher, you’d do the following:

  1. Make sure that all faucets are off and that nothing is using water. Also ensure that nothing (and nobody!) will use water while the dishwasher is run.
  2. Read your meter and write down the value as accurately as you can.
  3. Run the dishwasher through a full cycle.
  4. Read your meter again.
  5. Subtract the second reading from the first, and multiply the result by 7.48 to convert from cubic feet to gallons. This is how much water was used.

While your appliances and such will surely give different results from mine, I nevertheless thought it would be instructive to share some of what I learned:

  • Our dishwasher uses about 2.6 gallons per normal cycle.
  • Our front-loading washing machine measures its load and varies the amount of water it uses accordingly. A full load (with jeans) used 22.4 gallons, while a somewhat lighter load used only 19. I ran a couple of different loads and averaged the result, coming up with 20.2 gallons per load.
  • Running the front two zones of our home’s watering system consumed a total of 76.3 gallons.
  • The four zones that water our backyard all told used 195.2 gallons.

Reviewing my results, the dishwasher seems pretty efficient to me, and very likely beats hand-washing the same number of dishes (we only run the dishwasher when it is full, of course). While the 20 gallons used per washing-machine load doesn’t sound terrible, some Internet research reveals that today I could buy a washing machine that uses about half that amount of water. As for the yard water, while we don’t run the system (a combination of sprinklers and drip) for a good part of the year, to me 270 gallons (combined front and back) seems like a lot during the summer when we do. The yard thus seems the best place to concentrate our initial efforts. At first we plan to convert the remaining sprinklers to drip, and then we’ll re-measure our usage. After that, we’ll start looking into graywater…but I’ll leave that subject for another post!

The world is changing, and we need to change with it. Lawns and other water-thirsty plantings may look pretty, but using the limited amount of potable water we have available to us to keep things looking pretty just doesn’t cut it anymore. Let’s do what we can to minimize water waste and only use our valuable Hetch-Hetchy water where we absolutely must: for drinking, washing, and bathing. And let’s make sure that even in those cases, we only use what we truly need, saving the rest for others and for our own uncertain future.

As I tweeted earlier this week (@walkingRWC), Howie’s Artisan Pizza is open! You wouldn’t know it from their website (as I write this, it still says “Coming Spring 2015!”), but Howie’s had their soft opening this past Wednesday. Fortunately I was running errands that morning and happened to notice activity. Along with some friends, my wife and I ran over there and had a delightful lunch. Howie himself stopped by our table and we had a brief chat. He’s excited to finally be open!


Our Howie’s (as opposed to the one in Palo Alto) has a really nice bar, as you can see in the above photo. For those who have been to Palo Alto, know that our restaurant has a wider array of items on the menu than can be found down there: ours includes burgers, for instance. Howie’s pizza is really good: the crust in particular is excellent. But it is the outside patio that really makes this place special for me: we sat out there and found it very comfortable.

Do take a look at their menu, and consider giving them a try. I for one think that Howie’s is a great addition to the Redwood City restaurant scene, and I was very happy to be able to personally welcome Howie and his crew to Redwood City.

3 thoughts on “Measuring Up

  1. Pingback: To Fetch a Pail of Water | Walking Redwood City

  2. Thank you for the very practical tips. I’ve been wanting to measure the water usage of my washing machine but was befuddled by the meter. Would love to hear more about what you learn about gray water. I wish all that shower water (besides just the warm-up water) could be used to flush the toilet and water my trees.

    • You’re welcome. We’re definitely going to explore gray water setups and I will write about our successes and failures when I have something meaningful to report. Thanks for reading!

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