For a house that I'm in the process of buying, there is what I think is called a "catch basin" in the backyard (under a manhole-looking cover). It seems that the kitchen sink may be draining into this, which results in some food/etc items appearing in there.

A home inspector warned me about this (the catch basin should be for storm drains, but appears to have sanitary sewage in it), but the owners said that a kitchen sink draining to a catch basin is normal in older homes.

Around the internet, I can see some vague off-hand references to kitchen sinks in older houses draining into a catch basin, but I have trouble finding detailed information. Is this indeed common and okay? What is the point of this system, and why would modern homes no longer do this?

The house in question is rather old (built around 1920). It's one of the million bungalows around the Chicago area.

2 Answers 2


The point of that system was convenience. Plumbing was expensive and time-consuming 100 years ago. Whether it's common depends on the neighborhood and the city, of course.

Whether it's acceptable now depends on your local ordinances. Most "gray water" is required to pass through an approved septic system. I'm surprised that local code doesn't require an update for home sales. Frankly, I wouldn't want food and other waste decaying in my back yard, but that's just me.

  • yeah, I think that your statement about decaying food is why it's not common (and possibly not legal). Commented May 18, 2016 at 21:18

To clarify: about your statement that the catch basin should be for storm drains... yes- storm drains can use catch basins. But I'm pretty sure that in this case the sink water is draining into the city sewer. This was a regular design in Chicago, but I don't think it's common in the rest of the US.

I think it's safe to say that the design is not popular with homeowners because the basin will require occasional cleaning.

They did this because they cared about the public water works. The catch basin is supposed to help collect fat and other solids before they enter the city sewer... which could cause blocked or slowed drains.

  • Are you saying that the basin isn't, as the OP surmised, for storm water, and that it actually flows through to the municipal treatment facility? You might edit to clarify that point.
    – isherwood
    Commented May 18, 2016 at 21:17

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