Many of the older cities in the Chicagoland area have combined storm and sanitary sewers, meaning that the rain water drainage is collected through the same pipes as the sewage from houses.  This type of system is almost never used anymore when constructing a new system, but many of the older cities still operate this way.

In these older cities with combined sewers it’s very common for houses to have a grease trap built in.  Because the sewer system is combined, and because back when the system was built it couldn’t handle grease very well, grease traps were a way to prevent grease from entering the sewer system.  Here’s a brief description of a grease trap.

A grease trap is a pit buried underground where water from the kitchen drain runs to.  The exit pipe to the sewer is elevated a little bit from the bottom so that there’s always some water in the pit.

There’s a trap built over the sewer pipe, so that grease floating on the surface of the water is held back, but the water is able to run under the trap and out the sewer pipe to the sewer main.  Any solid debris will settle to the bottom.

This way the grease is held back out of the sewer system.  Note that only water from the kitchen flows into the grease trap.  There’s no water from any other sink and certainly no water from any toilet coming into the grease trap.  But there might be water from your gutters flowing into the grease trap.  Where your gutter downspouts go underground they generally empty into the grease trap.

With this arrangement you’ll need to clean out the grease every so often.  This used to be a much bigger issue back when we used a lot more grease in our cooking.  Now you should just throw away your grease rather than putting down your kitchen sink drain.  So how often you need to clean out the grease trap depends on a lot of factors, but it’s likely to be many years (probably a decade or more) before anything will need to be cleaned out.  You can hire somebody to do this for you, or you can just lower a bucket on a rope to scoop out the grease and discard it.

In well over half of the grease traps I see now the trap has completely deteriorated, usually to the point where it’s completely gone.  This isn’t a problem anymore and I don’t recommend that you do anything about it.  There’s just no reason to.  And some grease traps have been bypassed, so that the drainage from the kitchen goes directly to the sewer and doesn’t go into the grease trap at all.

These days the biggest issue with a grease trap is the condition of the ring and the lid.  If the top concrete ring is damaged or the metal lid is broken then somebody could fall through.  But as long as the ring and lid are in good condition then you have very little to worry about with a grease trap.

 

 

Inspection Overview
Why Get a Home Inspection?

Recent Posts

Don’t let your pipes freeze

I’ve heard the question many times: How low should I set my thermostat if I leave town in the winter, to save money but prevent my pipes from freezing? 65 °F?  60 °F?  50?  I

Wood shrinkage

Let’s talk about wood shrinkage. Your hardwood floors are the place where you’re mostly likely to see the problems associated with wood shrinkage, but old panel doors can also experience problems.  In floors, as the

Window condensation

Condensation on windows is a problem that I see a lot in the winter, and I see the damage from window condensation year round.  Here’s some information about the issue. Condensation will occur on a

Attic condensation

Water is your home’s number one enemy.  I’ve said that before, I’m saying it now, and I’ll say it again. Water in your attic can cause problems including mold growth, deterioration of the roof’s plywood

Request Inspection

More Posts You May Find Interesting

Don’t let your pipes freeze

February 7th, 2024|Comments Off on Don’t let your pipes freeze

I’ve heard the question many times: How low should I set my thermostat if I leave town in the winter, to save money but prevent my pipes from freezing? 65 °F?  60 °F?  50?  I

Wood shrinkage

January 16th, 2024|Comments Off on Wood shrinkage

Let’s talk about wood shrinkage. Your hardwood floors are the place where you’re mostly likely to see the problems associated with wood shrinkage, but old panel doors can also experience problems.  In floors, as the

Window condensation

January 10th, 2024|Comments Off on Window condensation

Condensation on windows is a problem that I see a lot in the winter, and I see the damage from window condensation year round.  Here’s some information about the issue. Condensation will occur on a

Attic condensation

January 8th, 2024|Comments Off on Attic condensation

Water is your home’s number one enemy.  I’ve said that before, I’m saying it now, and I’ll say it again. Water in your attic can cause problems including mold growth, deterioration of the roof’s plywood

Priorities

December 22nd, 2023|Comments Off on Priorities

Here’s a short quiz on energy efficiency priorities. Suppose you have two cars, and both get driven about the same number of miles.  One car is kind of old and only gets 20 miles per

Garage Fire Separation

December 18th, 2023|Comments Off on Garage Fire Separation

Separating the house from the garage against the spread of fire is an important part of home safety.  Here are some of the rules that the current version of the International Residential Code (2021) requires.