This might be more appropriate as a community wiki...
We have a septic system and I'm extremely paranoid about what can (and cannot) be put down our sink drains. I know the general answer is "nothing but water" but I'm particularly curious about:
How careful should I be?
-M
Tooth paste and soap (even a little anti-bacterial) are certainly fine. Basically, you just don't want to put any harsh chemicals in there that will kill the bacteria eating away at the waste.
I would avoid food and thicker items as they will not break down. I try not to allow hair, coffee grounds as they might not break down. I would definitely avoid paint.
Also avoid paper products that wont break down. Feminine products can cause havoc. Almost all toilet paper is septic safe these days, but read the packaging to be sure.
If you just bough a new house, or built one, I would recommend you have someone come out and pump the basin sooner that later. That way you know for sure that the tank is clean and in good working order and you can have a fresh start. I have heard way to many horror stories for new builds where the contractors used the tanks as a trash can and that later caused problems. Then remember to have the system flushed out every 3-5 years based on usage and local laws.
If you have a garbage disposal, don't use it. Just throw the food away. Keep extra solids to a minimum.
All the things you asked about are fine avoid pouring harsh chemicals down the sink in large amounts. I have never seen a laundry clog a septic system up and we have been installing and pumping systems for 20 years and I mean never. ou do however want to avoid the garbage disposable it is one of the worst thing you can do to a sytsem. Think of it this way your body when food enters it breaks it down and suck all the valuable stuff out of the food to feed you body. It is then disposed of after it has been thoroughly broken down in your body. When you put food down the drain or garbage disposable the septic system has to break it down from start to finish.This make bacteria much more active and propagate to levels not needed they also produce waste in the form of nitrogen that's the balk scum in the clarifying area of an aerobic septic system. So more food more Bactria. From years of experience I will say this a family who uses the garbage disposable lets say just two people this just happened, and I've seen it over and over who used the disposal daily will need a aerobic system pumped every 2 years as opposed to 7-8 years for a family who doesn't use a disposal.
