A letter writer says my Sunday story examining per-capita water usage in San Joaquin County was “all wet.”
Specifically, he didn’t like my “claim” that Lincoln Villagers guzzle at least 50 percent more water than their neighbors.
It’s true that calculating water usage can be tricky, especially in the case of Lincoln Village. Larger water providers are required to report such information to the state based on specific methodologies. I had to figure out Lincoln Village on my own.
But I was very careful and conservative. If anything, the difference is even greater than I reported.
So, in the interest of transparency, here goes:
While there are no meters in Lincoln Village to track how much water any one customer uses, we do know how much water is going into the neighborhood as a whole. In the past 20 years that total has varied from about 450 million gallons per year to about 550 million gallons per year, according to data provided by San Joaquin County.
According to the U.S. Census Bureau, 4,381 people lived in Lincoln Village in 2010.
So if we divide the total volume of water by the number of people, and then divide again by 365 days in a year, we come up with a rough range of 281 gallons per person per day to about 344 gallons per person per day over the past two decades.
For comparison, in 2010 the California Water Service Co. in Stockton calculated a baseline water usage of 182 gpd, and the city of Stockton calculated a baseline water usage of 195 gpd.
Of course, it’s not that simple. You really can’t look at just one year and get a good idea of any district’s water usage. Drought and economic distress can create aberrations in the numbers.
So I attempted to calculate Lincoln Village’s water use the same way other cities did: using 10-year averages.
Stockton came up with its 195-gpd baseline by averaging the years 1999 through 2008. When I do the same math for Lincoln Village, I get 324 gpd. That’s a 66 percent increase over neighbors within city limits.
Cal Water came up with its 182-gpd baseline by averaging the years 1996 through 2005. When I do the same math for Lincoln Village, I get 316 gpd. That’s a 73 percent increase over neighbors in central Stockton.
Lodi came up with its relatively high per-capita figure of 248 gpd by averaging the years 1997 through 2006. When I do the same math for Lincoln Village, I get 317 gpd. That’s a 28 percent increase.
Let’s really give Lincoln Village the benefit of the doubt and look at the 10 years from 1990 to 1999, which includes the tail end of a major drought when water usage dropped significantly and abnormally. When I do the math for Lincoln Village, I get 289 gpd. That’s still by far the higher than the other cities, which based their analyses on non-drought years.
Finally, let’s look at just one year — 2010. This is the year Lincoln Village saw its lowest water usage in the past decade. Its per capita rate? Still 307 gpd. That’s 57 percent higher than Stockton and 68 percent higher than Cal Water the same year.
The only thing I didn’t factor into the analysis were population changes prior to 2010. But Lincoln Village is an established area that likely did not grow much in the preceding years. And even if its population 10 or 15 years ago was smaller than it is today, that would make the per-capita water usage numbers look better, not worse.
Just about any way you cut the numbers, Lincoln Village does indeed have a higher rate of water use per capita. And most often, the difference is, indeed, greater than 50 percent.