The Cloaca Maxima project

Someone finally acts on one of John Newmeyer’s bright ideas: analyzing municipal sewage to estimate drug consumption.

Years ago, John Newmeyer of the Haight-Ashbury Free Clinic proposed what he called the analyzing sewage as a means of estimating the volume of illicit drugs used in a city. He called it the “Cloaca Maxima project.”

I think he was joking — Newmeyer’s creativity and sense of humor are both so extraordinary that it’s sometimes hard to tell which capacity he is exercising at any given moment — but I thought it was a great idea, and I’ve been puzzled why no one picked it up.

Well, a bunch of Italian researchers have finally done it: they’ve tapped the River Po, and calculate that the 5 million people living in its basin use about 4 kilos of cocaine per day, which at $100 per gram is worth about $150 million per year. (The reporter seems to have dropped a zero in calculating the daily street value, and I have no idea why he’s using U.S. rather than Italian street prices.)

The article, like most newspaper accounts concerning illicit drugs, is somewhat more breathless in tone than its substance justifies.

First, while $150 million a year sounds like a lot of money, it’s a little bit hyperbolic to talk about its “staggering” economic impact. If the Po basin has 5 million residents, and if the GDP per capita in that region were $30,000 a year (probably a substantial underestimate, given that Italy’s GDP/cap for 2004 is reported at almost $28k, and Northern Italy is much wealthier than the rest of the country), then the GDP of the Po basin would be about $150 billion, which would make the cocaine traffic about 1/10 of 1%. The comparable figure for the U.S. is between 3/10 and 4/10 of 1%.

Second, while the typical or median cocaine user uses much less than 100 mg. per day, the mean quantity consumed per user per day is probably higher than that. If the region had 10,000 really heavy users, averaging 150 grams/year (a daily use of just under half a pure gram — call it five lines, or ten rocks), that would account for the total estimated amount. Even if all the heavy users were in the 15-35 age bracket, that would be a little less than 1% of the population in that age group. So while the result suggests that the surveys underestimate the overall number of cocaine users — not really a surprise — it doesn’t suggest that the Po Valley has an especially bad cocaine problem.

Now that the method has been demonstrated, it’s time to think hard about adding it to our rather narrow repertoire of national drug data collection efforts. It’s probably pretty expensive chemistry, but expensive chemistry is much cheaper than cheap survey work. Cloaca Maxima wouldn’t tell us much we don’t already know about cocaine, but it might be quite interesting on drugs still on the upsurge, especially because it would naturally provide localized data. If you were the police chief in Boston, wouldn’t you want to know about it if the methamphetamine-metabolite content of the Charles started heading up?

Author: Mark Kleiman

Professor of Public Policy at the NYU Marron Institute for Urban Management and editor of the Journal of Drug Policy Analysis. Teaches about the methods of policy analysis about drug abuse control and crime control policy, working out the implications of two principles: that swift and certain sanctions don't have to be severe to be effective, and that well-designed threats usually don't have to be carried out. Books: Drugs and Drug Policy: What Everyone Needs to Know (with Jonathan Caulkins and Angela Hawken) When Brute Force Fails: How to Have Less Crime and Less Punishment (Princeton, 2009; named one of the "books of the year" by The Economist Against Excess: Drug Policy for Results (Basic, 1993) Marijuana: Costs of Abuse, Costs of Control (Greenwood, 1989) UCLA Homepage Curriculum Vitae Contact: