From Conservation


A decoupling drama plays out in San Jose

The San Jose Water Company recently proposed a significant rate increase, and its customer are understandably unhappy. Their discontent is an ironic result of success in conserving water.

Over the past year I’ve blogged about my research with Youlang Zhang and David Switzer on public and private water utilities’ responses to the drought that gripped California from 2014-2017. One of our most interesting findings was that California’s private, investor-owned utilities conserved significantly more water than government utilities. We argued that a main reason for the difference was politics and California law, which allows rate decoupling for private water utilities.*

The timing of the San Jose story was uncanny: I wrote my 2018 water conservation update just as SJWC was filing its request for the rate increase. The story of conservation and rates in San Jose is a useful illustration of why decoupling is so economically effective but politically perilous.

One city, three water systems

San Jose is unusual among large American cities in that three separate utilities provide drinking water service to its residents. The San Jose Municipal Water System (SJ Muni) is governed by the San Jose City Council, which sets the utility’s investment, operating, and financial policies. Two private water systems also serve San Jose: Great Oaks Water Company and San Jose Water Company (SJWC). Corporate boards and executives make investment and management decisions for these systems. Serving a population of more than a million, SJWC is the giant of the trio; but SJ Muni and Great Oaks are also large, each serve populations of around 100,000.

Importantly, very different processes govern price-setting for the three systems. San Jose’s elected City Council sets rates for SJ Muni. As investor-owned systems, SJWC and Great Oaks set their rates through the California Public Utilities Commission, whose members are appointed by the governor. That means San Jose voters can influence SJ Muni’s rates through their elected councilmembers. Rate-setting for SJWC and Great Oaks is a more technocratic affair, with the process handled mostly by lawyers, engineers, and economists at the CPUC.


All three systems charge fixed monthly service fees plus volumetric prices. However, their volumetric rate structures differ in subtle but important ways. The two private utilities employ inclining block rates, which charge progressively higher unit prices as volume increases. For example, SJWC customers pay $3.20 per hundred cubic feet (ccf) for the first three ccf; prices jump to $4.80/ccf for the next 15 ccf, and then to $6.40/ccf for volume beyond 18 ccf per month. Great Oaks uses a similar three-block rate structure, although its rates are considerably less progressive. SJ Muni uses a flat rate: customers pay the same unit price for all water, regardless of how much they use. Here’s how these prices translate into bills for demand ranging from 0-30 ccf per month:

Hint: the action is on the right end of the graph

Great Oaks’ prices are lowest overall. SJ Muni’s and SJWC’s prices are similar at low volumes, with the private company’s total prices about $7-10 higher through the first 15 ccf. Without detailed financial, operational, and customer data, it’s impossible to say whether that gap is justified. We can say that the gap widens at higher volumes due to SJWC’s more progressive pricing: at 40 ccf/month a SJWC customer pays $52.09 more than a SJ Muni customer. That means SJWC likely gets significantly more of its revenue from the high-volume customers who pay high prices for water.


Is water consumption in San Jose consistent with those differences in pricing? This chart shows SJ Muni’s water conservation from 2015-2018, and population-weighted conservation for SJWC and Great Oaks for the same period, compared with the same month in 2013:

Source: California State Water Resources Control Board

Notice how the green (private) line is close to but usually slightly above the blue (SJ municipal) line? Overall conservation tracks pretty closely for public vs. private over the four-year period, but San Jose’s private systems have averaged about 1% more savings.

The difference in per capita water use is much more noticeable; here’s residential gallons per capita per day in 2018:

Source: California State Water Resources Control Board

San Jose’s private utility customers are much more conservative with water than are SJ Muni’s customers, using about eight gallons per person less water on average. The disparity is greatest during the seasonal peak period when supply stresses are also greatest.

Decoupling to the (utility’s) rescue!

In 2018, SJWC’s water customers were so conservative that the utility had a $9 million shortfall in sales revenue. California’s policy of rate decoupling allows the company to make up that shortfall with a rate increase in 2019. San Jose residents and lawmakers are angry that their reward for conservation success is a rate hike. Flat rates help keep SJ Muni’s revenues steadier and so spare the city council from the citizen wrath that such a rate increase might unleash.

Lots of things cause people to use more or less water, and so we can’t say for certain that prices drove the conservation patterns we see in San Jose without detailed customer-level data and a carefully-designed study. But it’s fair to say that San Jose’s experience is consistent with the public-private differences we see in the rest of California. Without decoupling, it’s unlikely that private utilities would use progressive pricing and risk the kinds of revenue losses that they experienced in 2018.

Economics is supposed to be the dismal science and politics the art of the possible. But for California water, the opposite seems to hold: decoupling makes conservation economically viable for private firms, while politics forces governments into difficult choices that can mean financial success at an environmental cost.


*The full study is available from Policy Studies Journal.

SJ Muni’s flat water rates vary by geographic zone. The graph here uses a simple average of those rates.

Right on the money

A California surprise: update

Post-drought porn

California has been enjoying a great deal of rain and snow over the past several months—a pleasant rebound in precipitation after the brutal drought that plagued the state from 2011-2017. It’s now early 2019, reservoirs are full, the mountain snowpack is deep, and water managers in the Golden State are breathing easier than they have in a long time. Though water use has crept up since the end of the drought, overall water consumption remains lower than its pre-drought levels.

A California surprise

A surprising finding emerged from my analysis of California’s drought data with Youlang Zhang and David Switzer: the state’s private, investor-owned utilities conserved significantly more water than did local government utilities during the crisis. We linked the difference in drought response to the institutions that govern water finance. Nerds interested readers can read the full study in Policy Studies Journal for the details.

In a blog post last summer, I observed that a public-private conservation gap of 2-3% persisted in 2017 even after the drought ended, and wrote that financial imperatives would likely cause the trend to continue:

This consistent public-private difference lends greater weight to the idea that rate decoupling facilitates water conservation for private utilities, and that political constraints hamper public sector conservation. If 2018 holds to form, public and private conservation will converge in the spring and diverge again in the summer and autumn.

If financial and political considerations are really behind the public-private differences in conservation, then it stands to reason that the greatest differences would come during summer months, when water demand–and therefore rate revenue–fluctuations are greatest.

Not actually the author. I might have doctored the image a bit, too.

Now that full 2018 data are posted, it’s time to revisit conservation performance for the Golden State’s water utilities. Was the forecast valid? Did private systems conserve more than public systems again last year?

Are my water conservation predictions any better than my NCAA Tournament picks?*


Overall urban water use remained significantly lower in 2018, with average monthly conservation of about 14% compared with 2013. The public-private disparity in overall conservation also persisted. This graph plots average conservation (relative to the same month in 2013) for public and private utilities from January-December 2018:

Data: California State Water Resources Control Board

As you can see, public and private conservation moved in pretty close parallel through 2018, but private utility conservation was consistently higher than public. The difference was negligible during winter months, but during the May-September peak demand season, California’s investor-owned utilities saved an average of 2.3% more than their local government counterparts.

As always when discussing water, it’s important to give percentages some context. Had public utilities saved at the same rate as private utilities in 2018, the difference would have been about 27 billion gallons—more water than San Francisco uses in a year.

Decoupling, man. Decoupling.

The persistent seasonal swing in public-private water conservation suggests that the difference is due to differences in outdoor irrigation behavior. That the pattern is now consistent over three years adds to the mounting evidence that rate decoupling encourages conservation for investor-owned water systems.

This isn’t a story of environmental angels or devils, it’s about governance institutions and the incentives that they create. In light of the political challenges of managing local government water finance, it’s impressive that public utilities have continued to conserve as much as they have—a testament to local water managers’ commitment to efficiency in the face of political headwinds.


*They could hardly be worse. I didn’t get a single Final Four team right.

Perverse incentives

Devils (and angels) in the details, Part 2

It’s always about the money.

In early January the California Water Board released its draft proposal for a statewide low-income water bill assistance program. My last post summarized the path-breaking proposal and its promise for addressing affordability in the Golden State. It’s an admirable piece of work on a challenging and complex issue. The next couple posts wade into the tall policy grass in search of snakes. This one looks at the volume of water to be subsidized under the proposal.

Assistance for how much water?

An assistance program for water implies that there is some level of water consumption that is socially important, and that without assistance, water consumption would either fall below that level or force households to sacrifice other essential goods in order to pay for water. What is that level of water consumption? How much water is so important that taxpayers should subsidize it?

For California’s draft assistance proposal, the answer is 12 ccf (about 9,000 gallons) monthly per household.

Consumption in context

Not all residential water use is the same. Public policy discussions of water affordability are mostly concerned with essential needs like drinking, cooking, cleaning, and sanitation. We’re not generally concerned with the affordability of watering lawns, washing cars, or filling swimming pools.

Probably not worth subsidizing

The proposal’s 12 ccf price guideline implies 75 gallons per capita per day (gpcd) for a family of four. To give some context, California utilities average about 100 gpcd, which makes 75 gpcd seem pretty low. But it’s much higher than California’s 55 gpcd water efficiency standard (set to drop to 50 gpcd by 2030), and higher than typical water use in many California communities today. My own past affordability analyses have assumed 50 gpcd for essential use*; conservative San Francisco already averages just 42.4 gpcd for overall demand (not just essential use).†

There’s nothing magic about any of these numbers; in the end, the level of water consumption that is deserving of public subsidy is a decision to be made through the democratic process. But 12 ccf is a lot of water if the policy’s aim is to provide for essential water use. The draft proposal notes that the 12 ccf level is intended to allow for larger households and “modest amounts of outdoor irrigation.”

A perverse incentive

Why does any of this matter? Beyond the normative question of whether taxpayers ought to subsidize outdoor irrigation, a 12ccf standard may have the unintended effect of pushing water utilities toward less affordable, less conservation-oriented pricing.

Low fixed rates and low prices for essential water use make water affordable for everyone, whether or not they participate in an assistance program. Coupled with progressively higher volumetric prices, such rate structures help keep water affordable and encourage conservation. Unfortunately, many utilities have recently responded to falling average demand and revenue volatility by raising fixed rates and imposing higher costs for low-volume use. That’s good for utility revenue, but bad for affordability.

That’s where the perverse incentives creep in. A 12 ccf standard for assistance is likely to exacerbate the trend toward utilities raising fixed charges and low-volume rates. With the state’s assistance program providing aid to low-income customers, utilities can raise rates on volumes below 12 ccf with less concern for affordability impacts. That will naturally dampen the conservation incentive, as higher priced water becomes less expensive. Less obviously, higher prices for lower volumes will exacerbate affordability problems for anyone who is not enrolled in the assistance program. The draft proposal assumes an 84% participation rate; for the 16% of households who don’t participate (for whatever reason), affordability will probably get worse.

A footnote acknowledges a danger of strategic rate-setting (told you I’d get into the weeds!), observing that systems could respond to the assistance program by “shifting the rate burden to consumption levels below 12 CCF, and thus elevate the benefit for eligible households.” Apparently the concern is that utilities will game the assistance program as a means of channeling more state money to local customers. But from an affordability perspective, the more worrisome prospect is that the state’s assistance program will incentivize regressive pricing that ironically makes water less affordable for many.

This perverse incentive will exist no matter what volume is subsidized, but the greater the volume subsidized, the more perverse the incentive will be. If an assistance program is supposed to support a human right to water, then a more modest 6-8 ccf standard for support is more defensible and less susceptible to rate design gamesmanship.



*My January 2018 article on affordability measurement prompted a grouchy email from a San Francisco official who complained that 50 gpcd was an unrealistically high essential volume for evaluating affordability

I chuckled when typing: “conservative San Francisco.” Our language is funny, sometimes.