Smells in Bathroom

[joddle]

Can't find a better place to post this - mods please relocate if necessary.

Hi - our holiday property is in Spain and as it is a little way from the town, like all villas in the area has a septic tank - a two chamber system.

Normally this gives no problems but if the property is left empty for more than a few weeks at a time, we get a smell of sewers in the bathroom. Strangely this is not when we first arrive but after the toilet has been used - then the smell arises in the bathroom and remains for about a day and eventually disappears with continued use of the facilities. Things remain fine from then on until the next time the villa is vacated for a period then used again. This only happens in the first bathroom from the septic tank - all other rooms with sanitary ware are unaffected.

We don't seem to have any blockages and the pipes are all plastic and we can see most of the system under the villa. No cracks or leaks at all.

I have a suspicion of two possible causes.

The first is the system has no vent pipe and the closest inlet to the tank is the bath waste with a shallow trap which may possibly dry out therefore admitting the smells. However we always leave the plugs in when away to help prevent this - and also we flush all the bathroom fittings on arrival so know all traps are full once we arrive - yet the smell still comes up in the first 24 hours or so. The last time we were only away for 8 weeks and the weather has been pretty cool so I don't think the traps would have been totally dry anyway - I don't know though.

The second is we suspect the bio action may stop or slow when the system is not being used regularly and so once we disturb it again on arrival by using it again, maybe that starts off a more vigourous reaction when we first flush water into the tank and more gas is being created than normal ? Again a guess - more info needed.

Anyway your opinions and any advise welcomed. For us the problem is managable but we also let the villa in the holiday season and would not want a client to have to come across this problem - although this usually does not happen as bookings are pretty well back to back but with a declining market we can't assume this will always be the case - hence the need to find a solution as soon as possible.

 

[foxhole]

The first use after a while will break the surface in the septic tanks allowing gases out and hence the smell, leaving plugs in will have no effect since bath and sink have overflows which circumvent this allowing smells out, the smell then dissipates over the 24hours and you nose becomes more accustomed.
[Had a holiday next to a working dairy farm, smell was horrendous but after a few days we no longer noticed.]

 

[longdogs]

Don't know much about septic tanks but found this:

http://www.eco-habit.co.uk/default.asp?contentID=699&gclid=CIbBipz5v7QCFTDMtAodrwYA8Q

Have you looked to see if there's a Spanish farmer under your villa growing lettuces?

 

[joddle]

The first use after a while will break the surface in the septic tanks allowing gases out and hence the smell, leaving plugs in will have no effect since bath and sink have overflows which circumvent this allowing smells out, the smell then dissipates over the 24hours and you nose becomes more accustomed.
[Had a holiday next to a working dairy farm, smell was horrendous but after a few days we no longer noticed.]

Will an open pipe to the outside help ? - ie a vent pipe - there is a place I can add a thicker type drain tube to the main pipe wher an old sink a
was in the past fitted but the position is not used any more so I could open up that outlet and extend a pipe into free air with a suitable bird proof ending.

 

[joddle]

Looking closer at the bath outlet I noticed something which seemed to be partiially obstructing the drain. I had to remove the plug and plugholder to see what it was and it turned out to be a badly decomposed ring washer - and under the bath and on top of the trap was a rock hard and badly calcified rubber washer. Both items well past their use by dates so both replaced today and for good measure a dose of bio activator added to the system as the road kill dog would not fit into the pipe!! (joking!) . No smells so far so fingers crossed!!!