Two ?vent? in driveway

[kokain]

I find it hard to believe that I have an uncommon problem. I don't know much, but it doesn't sound THAT weird.

At the top of my driveway are two ends of 3" pipe. They both have slotted toppers on them. They are about 12 inches apart. The problem is that when a toilet flushes and I'm in the driveway I can smell sewer gas. I don't like the front of the house to stink. I would really like to cap these pipes. From my research I have found three explainations.

1. They are a dual cleanout. If so, I could cap both with screw caps.
2. They are part of the venting system. Which would mean at least one of them had to stay open.
3. They are there in case the main sewer backs up so the waste can go in the driveway and not the house. I don't want to think about the back up hitting the house!!!

Any suggestions? What info did I leave out?

 

[johnjh2o]

There probably clean outs. One is used to snake the line away from the house and the other is to snake the line towards the house. They can be plugged.

John

 

[LiQuId]

put a test cap on both and then flush toilets and use fixtures ( fill them completely and then drain ) you are looking for ( or listening for ) gurgling in the pipes, burping of the drains and generally poor working fixtures, if they run as normal then they are likely as john has said, dual cleanouts.

Seperatelly...what are you heating your house with? ( boiler, furnace etc. ) i strongly doubt that these are ehaust or intake vents being 3" piping, but It is not impossiblle.

a pic of the pipes would clear it up..... IF these were ehaust or intake you would definatelly not want to cap them.

 

[kokain]

Thank you guys. I figure they are cleanouts. I'll cap them and test my drains as suggested. Good call on the furnace exhaust, but mine are 2" pipes on the other side of the house. Is there any concern about the main line backing up into the house if I cap these? I have never seen anything come out of these pipes. I'll try to get some pics when I get home (I will prob forget).

 

[johnjh2o]

If they are clean outs, as most agree on. They should be pluged.

John