It was a long, slow hunt for data with variables aplenty: gallons, cubic feet, billing and meter sizes.
Reporters for APM Reports and Great Lakes Today spent nine months investigating the cost of water in the Great Lakes region. We began by sending records requests to the six largest cities that sit directly on the Great Lakes: Chicago, Detroit, Cleveland, Milwaukee, Buffalo and Duluth.
My colleagues and I knew rates were rising. But here's what we didn't know: by how much, how fast, who the increases were affecting most, any consequences from higher prices, and most importantly - why.
We asked for two main sets of data starting in 2007: water and sewer rates, and water shutoffs. We wanted water and sewer rates because they're billed together, and sewer rates constitute a significant portion of a customer's bill. We got similar rates for Phoenix to compare.
Getting the proper public data was a slog, which is typical for investigations like this. APM Reports spent months filing open records requests. Some cities were forthcoming with data on water billing and shutoffs. Others sent us the data but provided fewer years. Cleveland sent us data on water reconnections, but later told us they were inaccurate. One city, Milwaukee, was wholly uncooperative. It wouldn't provide historical sewer rates and fought our requests for data on water shutoffs. And Duluth officials initially wanted to charge us $92,000 for the information. (We negotiated a lower fee.)
After gathering as much data as we could, we began our analysis.
The money people pay for water combines two factors: rates and quantity. We had the rates. But to compare costs in different places, we needed to determine a standard amount of water.
We used the cost for a family of four using 50 gallons per person daily. APM Reports chose this number based on the recommendations of academic experts. Fifty gallons per person daily provides a conservative estimate that helped us evaluate the cost of the same unit of water in different regions.
It's important to note that water utilities bill differently: Some charge based on gallons of water, others on cubic feet. Some bill monthly, others quarterly; some just charge for water used and others add fixed fees.
Calculating the cost for a family of four using 50 gallons per person daily - 73,000 gallons, or 9,758.88 cubic feet, per family, per year - gave us an apples-to-apples comparison among cities with different billing methods.
We are also using 5/8" meter size, which, according to many of the cities, is the most common size for residential water customers. That's an important variable to hold consistent because the price of water is based on meter size.
As you can see below, we found that water rates increased in all six cities around the Great Lakes in recent years. Some of the increases were substantial.
Remember, this analysis may not reflect the precise cost of water in the cities because of different billing methods, consumption rates and other factors.
APM Reports amassed hundreds of thousands of rows of data. We grouped data by ZIP code because it was the best way to get a standard comparison among cities given the different formats in which we were given data. And with U.S. Census data - also released by ZIP codes - we could search for demographic patterns.
We found a strong correlation between water shutoffs and ZIP codes that are either low income or majority African-American or Latino. This led us to conclude that poor residents and people of color have been disproportionately affected by water shutoffs in five cities. (Milwaukee stopped shutoffs in 2015. Today the city adds unpaid water bills to a property's tax liens.)