Non vented plumbing in Costa Rica

[Nils Hammerbeck]

Greetings. I'm a CA architect living in Costa Rica. I confess I don't know plumbing logistics too well. Neither do the locals. I'm living in a jungle house that's about 15 years old, and all fixtures were installed without roof venting. It's on a septic tank with a leach field. There is a downstairs apartment and an upstairs one. The downstairs studio has a kitchen sink, a bathroom sink, a shower and a toilet. Upstairs has a sink and a toilet and we are about to add a shower and a kitchen sink. None of the system seems to drain well, and the toilet burps sewer gases. It's quite lovely. NOT! The structure is made of steel and concrete. I've been researching AAV's but don't really know where to install them. Is anyone out here able to help lend some advice?

 

[Terry]

A good article is this one
Helpful Plumbing Hints for Residential Construction by Bert Polk Plumbing Inspector Lincoln County

Basically, Every fixture should have a p-trap to prevent sewer gas from entering the home from the septic tank. Every p-trap should be vented to prevent siphoning of the water seal in the p-trap. Some of those can be done with AAV's (auto air vent) and you need at least one through the roof to open air for that to work. Venting is normally both negative and positive pressure, the AAV's work on negative.

Some fixture can share venting, called wet venting. Those are bathroom fixtures like the lav, tub/shower and toilet. Sometimes the lav is used to wet vent the other bathroom fixtures.
Fixtures that we don't wet vent are kitchen sinks, washers, and laundry sinks.

For a wet vent to work, the common piping needs to be large enough to handle both the water and air passing over it. A small pipe pulls with too much force.

Here the lav wet vents the toilet and the shower. The p-trap for the lav gets added at finish.
The trap on a toilet is within the bowl. Unlike the other fixtures.

I found this little tidbit about Costa Rica plumbing
"I’ve walked into a brand new $500,000 luxury home and gagged from the odor coming into every bathroom and the laundry room…"

 

[Sponsor]

 

[Nils Hammerbeck]

thanks for the info...yes, bad plumbing is common down here along with all the other trades...I'll read all of this and analyze my system prior to posting specific questions.

 

[hj]

A septic system is a closed system, so it needs at least one roof vent to relieve the pressure created by fixtures draining. Without the roof vent the pressure has to vent through the toilets or other fixture traps, causing the "burping" AND odors. AAVs CANNOT relieve this pressure so they are an ineffective solution to it.

 

[Nils Hammerbeck]

so we realized that a huge part of the problem was the septic tank being completely full. Thats has been remedied but we still have a closed system. I imagine the reason the vent goes to the roof is such that the smells are away from windows and such, as this vent will still be emitting the odors?

 

[Terry]

so we realized that a huge part of the problem was the septic tank being completely full. Thats has been remedied but we still have a closed system. I imagine the reason the vent goes to the roof is such that the smells are away from windows and such, as this vent will still be emitting the odors?

Yes, in our codes, no vents are near or below windows. We put them high, so that the prevailing winds can disperse them.