A septic isn't really an alternative to being hooked up to city sewage - if city sewage is available you generally have to hook up. It is a safe way to get rid of waste if no city sewage is available.

Bacteria naturally present in human waste multiply rapidly in the storage tank and essentially liquify all of the waste. Some things cannot be digested by the bacteria so they sink and become sludge at the bottom of the tank. Fats and oils float and become a foamy layer on the top of the tank. The liquid in between exits the tank into one or a set of perforated pipes (there are other distribution methods as well - this is just one) where the liquid seeps into the ground.

Yes, you have to be more careful with a septic. Frankly, however, the things you do for a septic are common sense things we should all do anyway, but:

1. No grease, oils, paint, etc. down the drain,
2. No flushing of tampons,
3. Avoid bleach tabs in toilets or too much bleach in laundry,
4. Either no disposal at the kitchen sink, or only use it to grind the incidental food bits that would end up going down the drain anyway. Food waste goes in the garbage or compost, not down the drain,
5. Despite all of the advertising to the contrary, no supplements (such as Rid-X) should be used.
6. If you are very careful, and your septic and drain field are properly sized, you may never have to pump. Most companies that pump septic tanks recommend pumping every three years. However - a septic tank is a biological system. Biological systems don't like upsets (like pumping), so it is better to actually measure sludge level and pump only if/when necessary (when sludge depth is greater than 1/3 of the height to the effluent line).

Alice, I pump every 3 years and the tank is typically about 3/4 full of sludge at that point. Once I went 5 years before pumping and the solids were within a foot of the effluent pipe. Is that an indication of a problem? I have a 1,000 gal tank, 2 leaching lines and a 2 bathroom house with 3 people living in it. At some point we may need to move one of the leaching lines to put an addition on the house. Is there additional work I should consider doing at that point (like installing a spare leaching line with a transfer switch)? Our local building inspector said he would allow one additional bathroom with the current tank, but would require a bigger tank after that.

Also, I've always heard that you shouldn't use colored toilet paper in a septic system because the color fibers don't degrade. Is that true?

I received a periodic inspection report yesterday.
System is 12 years old, never been pumped. Solids level:
Tank 1 = 0"
Tank 2 = 0"
Tank 3 = 0"

In a nutshell, waste goes into septic tank, excess liquid goes out into the drain field where it goes into the ground. Tank needs to be pumped here and there. There are drain field products in this drainage catalog which can give you a visual of what is going on.

http://www.ndspro.com/PDFs/Catalogs/NDS-Drainage-Catalog.pdf

@greasetrap: you should probably just get your tank pumped out more often, like every two years. Colored toilet paper should be fine. The buildup doesn't mean there's a problem, probably just heavy use, that's how it is supposed to work. Better to pump a bit more frequently, as you can check all is in order and keep solids from going out into the leaching lines.

greasetrap - I would take a hard look at what goes down the drain - that's a lot of sludge in such a short time. Do you work a job that results in a lot of dirt in the laundry? Put coffee grounds down the drain? Use a lot of harsh cleaners, such as bleach? Use those "flushable" wet wipes?

As to colored TP, while the fibers shouldn't break down slower, the dyes certainly won't help the septic bacteria. In addition, no other paper products, such as paper towels should go down the drain.

If you do end up having to move part of the drain field, I would definitely install another one at the same - dig once rather than twice.

I agree with alice's points above - seems fairly heavy sludge for this time period. Do you have an in-sink garbage disposal (garberator or whatever they're called locally)? They can cause a lot of extra load on the septic - meaning more stuff to digest - and for the most part, better to compost that stuff (but a separate topic). So in using one, fine to help get rid of stuff that falls down there anyway, but not recommended to use it as a dumping ground (as 'disposal' would imply).

Anyway, even if you are more careful, best to get it pumped out a bit more frequently. Above you (greasetrap) said the sludge was within a foot of the effluent pipe. That is dangerous as it means more likelihood the sludge will get into the leach field and sludge that up - which could mean an expensive repair and possibly digging up and replacing the leach field. I seem to recall that the general recommendation is that sludge should not be more than 1/3 of the tank; whether or not that general recommendation is correct, it's probably not a bad rule of thumb. And getting it pumped out 'too early' won't cause any issues (except cost some extra money, but still much less than repairing a failed leach field).

I will be building a retirement home next year that is in an area with all septic systems and have a question. Somewhere I read that one of the bigger problems in clogging up the field lines is lint from doing laundry if it gets past the tank. In thinking about it, this would seem plausible since I'm sure a lot of fiber from the clothes gets washed down the drain. And if that fiber makes it to the lines it could mat up and become impermeable.

Would it be advisable to install some sort of lint filter near the washer discharge to avoid putting it into the septic system? I have seen the socks that attach to the discharge hose that go into a laundry sink but plan on doing a more std. install with the drain pipe in the wall.

You could install an inline cartridge-type filter. If you google laundry lint filter you'll find several different brands.

Thanks aliceinwonderland_id. I saw a couple available and think I will plan on putting one in when the house is built. Not sure if it is really necessary but it won't hurt either. One has a stainless filter that is washable so you aren't having to buy rather pricey filters which seems like a good thing.

I'm going to need some advice on sizing a softener and will start a new thread when I get all the info together. Your advice is top notch and appreciated.

@greasetrap: it's possible that your bleach (and other strong cleaners) and backwashing the water treatment is slowing/harming the bacteria in the tank that treat and reduce the sludge. But anyway, having the tank pumped out a bit more frequently is probably doing enough for the time being.

I found the source below and several others on backwash/brine that say the same thing: in short, it can reduce biological activity in the septic tank, and also displace the sludge (because the brine is slightly heavier than the sludge) and increase the risk of solids getting to the leach field. Main recommendations (if disposed to septic) are to pump more frequently and check effluent filter in place.

http://www.dem.ri.gov/programs/benviron/water/permits/privwell/pdfs/backwash.pdf

The house we're building has a septic system...my first experience in my life with a septic is in the rental house we're living in while our house is being built. The landlord now has us use Rid-X every month so I assumed it was good for the septic system. aliceinwonderland_id, why is it bad to use?

It causes larger floating bits that then enter the leach field prematurely, causing it to plug more quickly than it should. Human waste contains all of the bacteria necessary for the septic to function properly.