Septic sytem used for 5 weeks out of the year- is this a problem?

We have a vacation home that we visit about 5 inconsecutive weeks out of the year. An older couple used it as their primary home for 3 years, before we bought it. What happens to the bacteria in the tank, since months pass between the times when we use it. I imagine that the water level in the tank drops (and probably dries up altogether) while we aren’t there. I’m just wondering if this will pose any problems. Does anyone have experience with a septic system that is used infrequently?

Having never been on a septic system, I can't speak to the septic tank question, but the P traps in the house will dry up, and critters can enter the house through the pipes. You should treat this like you were preparing for winter. RV antifreeze in the traps, including toilets. Water lines would not need to be drained unless the off season was winter, then they would need to be blown out or otherwise drained.

The tank won't dry out unless it has a leak. The waste falls into the tank; solids sink to the bottom (generally), and when the liquids reach the output baffles, they flow to the leach field. Since the leach field is underground, there's no real air movement to evaporate the stuff in the tank, so it stays full up to the baffles. The reason they need to be pumped out periodically, is that the tank fills with solids that either don't disolve or decompose, and the liquid level gets shallow. WHen new stuff comes in, some of the solids can get washed into the leach field, plugging it up since there's little room for the solids to settle out. Then, you need to dig it up, or find a place to install a new one.

Translation: You are fine, relax and have a cold one on the porch.

Thanks, everyone! When we leave and shut the water off, I always make sure the toilets have water (or RV antifreeze) in the bowl. Then, we put a layer of plastic wrap over them to ensure there isn't any evaporation. I also drain the water from the pipes, but we leave the heat on.

It sounds like the system will be fine, then. That's what you get when a city boy buys a place in the country!

The only proviso would be if this system had a pump to the leach field. Then I would make sure some water was entering the system enough for the pump to run once a month, lest it seize up.

I don't believe there is a pump, but I will have to check that. I think the leach field is in the yard, which is essentially on a slope. I'm actually not sure where the tank is located, but I believe the access pipe (for pumping) is located just inside the crawl space.