What is this and why is it there?

[msteger]

Take a look at the photo -

Just upstream from the sewer line's exit location in the basement (right side in photo), someone installed this contraption (two elbows and cleanouts) that goes down to the basement floor then rises back up to exit the home. I would consider this to be a trap. Behind this trap, is a concrete laundry tub. To the left is where the rest of the home's drain plumbing connects to this trap. I would expect that the location of the trap would promote clogs in the drain line. I am thinking this contraption is there because of the height of the drain from the laundry tub. Anyone else have an opinion?

Click to Enlarge

39.79 KB

[Jim Katen]

Take a look at the photo -

Just upstream from the sewer line's exit location in the basement (right side in photo), someone installed this contraption (two elbows and cleanouts) that goes down to the basement floor then rises back up to exit the home. I would consider this to be a trap. Behind this trap, is a concrete laundry tub. To the left is where the rest of the home's drain plumbing connects to this trap. I would expect that the location of the trap would promote clogs in the drain line. I am thinking this contraption is there because of the height of the drain from the laundry tub. Anyone else have an opinion?

That's a whole house trap. When I used to live back east, I saw them in a lot of older buildings. The idea was to prevent public sewer gas from entering private waste systems. It didn't work very well and it's a good place for clogs to occur. Most municipalities have moved away from the requirement for these things.

How was that waste line supported? If someone steps on that thing, it could break an make an unholy mess.

The laundry sink isn't vented and it connects to the main waste line with a sanitary tee on its side.

- Jim Katen, Oregon

[msteger]

Yep.. I noted that it looked like a home owner (or drunk Uncle Ned) did that plumbing job. I recommended having a licensed plumbing review the installation and make needed repairs. This wasn't a private waste system, but rather a public sewer.

There was nothing supporting that trap. The first thing I said to myself when I saw that was, boy, don't trip over that. In 7 years, I've never seen a whole house trap..it's always something new, eh? I've inspected homes from the 1700s all the way up to the present, and never saw one until today. Are you saying that in some areas, a whole house trap is common??

[Jim Katen]

Yep.. I noted that it looked like a home owner (or drunk Uncle Ned) did that plumbing job. I recommended having a licensed plumbing review the installation and make needed repairs. This wasn't a private waste system, but rather a public sewer.

Actually, it's waste piping until you get to a point 2' away from the foundation, then it becomes sewer piping. I didn't mean to refer to a septic system.

There was nothing supporting that trap. The first thing I said to myself when I saw that was, boy, don't trip over that. In 7 years, I've never seen a whole house trap..it's always something new, eh? I've inspected homes from the 1700s all the way up to the present, and never saw one until today. Are you saying that in some areas, a whole house trap is common??

Yes. In fact, in some areas it used to be required -- at least it was 30 years ago. Sometimes they were located below the basement slab so you might have seen some without knowing it. The only way to tell would be by looking at the peculiar arrangement of the cleanouts, which would look just like they do in your picture, but in the slab instead of above it. I'm sure that other east coast inspectors are familiar with these things.

- Jim Katen, Oregon

[Bill Kibbel]

Are you saying that in some areas, a whole house trap is common??

Very common. Some spots in the country still require them. Some were required only for one-story buildings. Sometimes they're outside, directly below the yard vent.

A main trap needs to have a fresh air inlet - on the house side of the trap.

[msteger]

Interesting.. first time I've ever see anything like this. If they've been in home's I've inspected in the past, they've always been out of view or under the slab. Thanks for the info, guys.

[SWagar]

I understand that in some older New England homes, since there was the

whole house trap not all fixtures had their own trap.

My Salem Mass home (built in 1932) had a whole house trap. It was added sometime later when the house was converted from septic to public sewer (or so I was told- before my time in the house).

[msteger]

Thanks guys.

[Bill Kibbel]

Looking for something else, I came across this in A Treatise On Architecture And Building Construction. It's an 1899 description of main traps.

http://chestofbooks.com/architecture/Bu ... Traps.html