Have you ever noticed those big cast-iron pipes sticking up out of the ground in various places around the outside of old houses? They’re old rainleaders. They took rainwater from the roof and brought it inside the house. From there, the water was either stored in a cistern or exited the house through the sewer system.
Here in the Twin Cities, if the rainwater left the home through the sewer system, it was probably connected to the sanitary sewer system. That’s the system that takes wastewater from our homes to a sewage treatment facility. The problem with dumping rainwater into these systems is that when everybody does it, our sewage treatment facilities can get overwhelmed. When that happens, excess water must be returned to our rivers and lakes without being treated. And that will include raw sewage, which is bad news.
We don’t want stormwater dumping into our sanitary sewer system. For this reason, just about all rainleaders you’ll find today have been abandoned and sealed off. Minneapolis has some good information about the process of disconnecting rainleaders on their website, along with a 3-page handout showing exactly how to do it.
The picture below shows the only rainleader I’ve ever found that hadn’t been capped off. Someone had placed the stone on top of it, but I removed the stone to show that the pipe was open.
Cisterns are big holding tanks for water. I’ve run across a handful of homes in Minneapolis with abandoned cisterns, but never an active one.
Rainleaders would direct water into these caverns, and a pump would take the water back out for watering the lawn or garden, or for non-potable water use inside the home. The diagram below is courtesy of Tom Feiza at How to Operate Your Home.
And the photos below show the most recent cistern we found at a 1909 Stillwater house.