Posts Tagged 'metric'


As I looked over some papers I received in the mail regarding my first residential water bill, I thought to myself, “Thank goodness my water usage is measured in CCF. I obviously know what CCF stands for, since it’s a common unit for measuring liquids in my everyday life. And of course, like most other Americans, I think about personal water usage in 100 cubic foot increments, so this will make it easy to correlate my daily water usage with my water bill readings. If I need to figure out how a 1.6 gallon per flush toilet impacts my water usage, it’s just a quick division by 748 to convert gallons to CCF. Monitoring my water consumption has never been so easy!”


For everyone who doesn’t work at the Bizarro Water Bureau, 1 CCF is 100 cubic feet (centum cubic feet), which roughly equals 748 US liquid gallons [1]. Neither CCF nor cubic feet nor 7.48 or 748 gallon increments are common measurements of liquid volume by individuals, so all water customers are starting from a disadvantage when attempting to evaluate their water bill.

This arcane measurement system means that every municipality has to take time and effort to explain the unit and its conversion. For example, the Portland Water Bureau’s CCF to Gallon Converter is just one of many explanatory pages and online calculators from municipalities across the country. Even though measuring water usage in cubic feet is reasonably grounded in technical reasons (based on pipe size, so sayeth a Portland Water Bureau representative when I inquired), it’s certainly not an intuitive measurement for end-users. Regardless of what unit of measurement is used at the physical water meter, the information ought to be re-framed in a way that’s immediately understood by end users rather than forcing users to speak the professional language.

Additionally, CCF is too blunt a measuring stick. With 1 CCF as the smallest billable unit, up to 747 gallons of water may swing from one billing period to the next. This means that you could reduce water usage by more than 8 gallons (30 litres) every day and not see an effect on a quarterly bill.

“OK smarty-pants, think up something better,” you say? Here are two ideas.

Idea #1

The metric system is uniquely suited for this sort of problem. The SI system of prefixes and interrelated units mean that smaller, everyday quantities (daily usage) scale easily to larger quantities (monthly or quarterly usage).

Consider an example reading of 20 CCF:

CCF 20 CCF 2000 cubic feet 14960 gallons (approx.)
Metric 56.6 cubic metre 56.6 kilolitre 56600 litres (exactly)

While cubic metres suffers the same fault as CCF of not being an everyday unit of measurement, it does have a distinct advantage of converting easily to litres. Although most Americans don’t think in litres as their primary unit of liquid measurement, nearly everyone is familiar with soft drink or booze bottles of the one or two litre varieties. And while the cubic metre is still a fairly large unit of measurement (equal to approximately 264 US gallons), it’s still significantly more fine-grained than CCF.

Idea #2

If municipalities just can’t bear the thought of being branded godless communists for using metric units [2], at the very least, bill per 100 gallons. Consider the same 20 CCF example again:

CCF 20 CCF 2000 cubic feet 14960 gallons (approx.)
Per 100 gal 149 × 100 gal 14900 gallons (exactly)

Average water usage will vary by personal habits, geographical region, housing type, and so on, but the USGA estimates water usage per capita per day at 80–100 gallons, so I think billing in 100 gallon units would be very intuitive. For those using more or less than the average, you could easily tell if you’re saving (or squandering) relative to the average by comparing your billed usage in 100 gallon increments to the number of days in the billing cycle (e.g. 90 day cycle with 90 × 100 gallon usage).

That said, 100 gallons per person per day is generally excessive compared to most of the world, so hopefully that average will drop. As time passes this would upset the easy comparison of days and 100 gallon units, but it would still provide a reasonable high water mark (bah-dump-cha!) for comparison against past usage. Eventually a lower multiple could be chosen if average daily usage drops far enough (e.g. × 50 gal), or a higher multiple chosen to correlate to average per month usage (e.g. × 1000 gal).

That’s great. But who cares?

Why all the fuss over a couple of lines on my water bill? Details matter. The intended audience should always be kept in mind with any writing, and bills are no different. Outlining water usage is a great way to highlight how much of this precious resource is being consumed, but if the presentation is too abstract then the information is lost on the reader.

  1. Don’t even get me started on the confusion between US and Imperial (UK) gallons, or the inane myriad of liquid volume units in the US customary system.
  2. Though if the heathens at the electric company can get away with using kilowatt-hours (kWh), I don’t see any issue here.


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