Lies, Damned Lies and Statistics

American novelist Samuel Clemens is said to have popularized the aphorism that there are "lies, damned lies, and statistics," pointing out the ways data can be misinterpreted.

Denver Water officials, for example, likely are disappointed that water use by households dropped only about nine percent during the 2026 drought year, even if a 20-percent reduction was the target. 

The degree of water conservation is understated. 

The Denver metro area has added a very large number of people and homes since 2000, so demand is naturally higher than it was two and a half decades ago. 

Denver Water's historical data show that total treated-water consumption in its entire service area was 83.6 billion gallons in 2000, when it served about 1.036 million people. By 2024 it was about 68.1 billion gallons, serving 1.301 million people. Thus, total consumption fell about 18.5 percent even while the population rose 25.6 percent.

The per-capita calculation is even more striking:

2000: 220 gallons/person/day

2024: 143.5 gallons/person/day

decline: 34.8 percent. 

From 2000 to 2024, for example, though housing units increased 48 percent, per-unit water consumption dropped 51 percent. 

Denver city	2000	2024	Change
Residential water sold	17.81 billion gal.	13.01 billion gal.	−27.0%
Housing units	251,069	372,123	+48.2%
Residential water per housing unit	70,934 gal./yr.	34,952 gal./yr.	−50.7%
Equivalent gallons/day per housing unit	194.3	95.8	−50.7%

There also is evidence that Denver Water’s consumption drops are not unique. 

Provider / region	2000 benchmark	Recent figure	Reduction	What it tells us
Denver Water — entire service area	220 gallons per capita per day	143.5 gpcd (2024)	−35%	Large decline despite 26% population growth
Denver city — residential, per housing unit	70,934 gal./yr.	34,952 (2024)	−51%	Best direct housing-unit comparison
South Metro Water Supply Authority	215 gpcd	~120 gpcd (2019/recent)	−44%	Particularly large reduction despite substantial population growth
Aurora Water	2000 baseline	Recent consumption >30% below 2000	>30%	Total water treated is now lower despite population growth
Englewood	2009: 149 gpcd	2019: 150 gpcd	roughly flat	Much less conservation progress in this particular period

The point is that residential water users have been reducing water consumption for decades, even as the population has grown and housing units grew 48 percent.

Water users also are not “rewarded” for that behavior. Since all fixed costs of water infrastructure still have to be supported, water rates actually climb as customers use less water. 

Of course, that might be the longer-term incentive for the water supplier. Any economist will agree that, for mass market goods (luxury goods are different), raising the price reduces the demand. So higher prices will create incentives for consumers to buy less. 

But the incentives are somewhat perverse. The reward for behaving responsibly is higher prices.