Pareto chart approach to reducing water usage in your city

Reducing environmental problems can be complex, but there is a very structured way of focusing on the right things, so you spend your time wisely.

One of the key aspects of this process is the Pareto principle. It states that 80% of the usage or impact of a metric come from 20% of the areas or users. While the percentages may not always come out this way, this helps keep everyone focused on the top issues, which can have benefits across the board, and help ensure the biggest issues are being worked on.

If you don’t have a Pareto chart for the processes you are responsible for, you need to create one!

Portland has taken the same approach to help address residential water usage. As reported by the Willamette Weekly, the Top 10 water users (“Hydro Hogs”) over a 12 month period were identified and listed by name in the article.

A top 10 list is great, but the Pareto chart makes this more visual, and can help reduce the list from the Top 10 to the Top 2 or 3 biggest users, which keeps everyone focused.

I took the data, and created a Pareto chart in Excel. I sorted by total gallons, but you should normally sort by dollars spent per year, to make it more financially-driven. However, in this case, water usage is a direct correlation to the cost of the bill, so the Pareto chart will look the same. For other utilities, like electricity and natural gas, that might not always be the case.

Top 10 Portland Water Users

There does appear to be a big separation between the first two residences, and the remaining 8. Therefore, if your job was to reduce residential water usage, you should focus solely on #1 and #2 on the list. The root causes and solutions that you come up with will likely be applicable to other users.

In addition, because we are bringing attention to the issue, it will have a psychological impact on others, who look at the list, and think “I don’t want to be on that list!”

By default, you will see some behavior changes from other residential users without any direct communication. In fact, the best way to make improvements with little effort is to develop competition. Check out this TED talk that elaborates on this point.

If you are asked to make some improvements in an area, use these simple steps to get started:

1) Define the problem (too much water being used)

2) Gather the data (usage by residence)

3) Prioritize the biggest areas (Pareto chart)

Now you are ready to gather a team together to decide if you have the right variable in your Pareto chart (maybe neighborhood, dwelling type or aquifer is better), and how best to approach the top users to identify improvement opportunities.

Check out the Pareto chart for largest US carbon emitting power plants >>>

What are the biggest water users in your city? company? building? department?

One Comment

  1. qmssAuthor August 30, 2013