Monday, June 11, 2007

A Word About Septic , Septic Design and Graywater

For those of you unfamiliar, most of the lots that are out in the countryside aren't connected to town sewerage, so you have to get your own septic tank. It is where all your wastes go after you flush your toilet or clear your garbage disposal, if you have one. We are opting to use compost for our organic trash instead of a garbage disposal, since Jan likes to garden with it. It's basically thrown in a container and fed to worms that make a juicy soil that plants love :-).

Graywater is the water flushed from your laundry machine, sinks and showers. Many green people use graywater to water plants, which is perfectly fine. You have to plumb for it, but Texas has restrictions that you can only use graywater from laundry machines as of now. We are plumbing for it, but I'm not sure if we are going to use it for watering yet. We will be using our rainwater collection for most of our watering needs.

Anyway, so we got the Septic guy out there. In Austin, there's a process you have to go through before you can get to building. It goes like this:

1. When plans are finished and engineered, go to the Travis County office and apply for your building permit. It's like $35 for the permit application. You'll get a building permit number, but the building permit takes time to process.
2. Tell your septic installer that you got your permit number, and you supply him with some documents and then he submits the septic design and application to the county office. ($460 fee for this)
3. Your building permit gets approved based on septic design, and it will take about 30 days for you to get your permit and septic design approved.
4. You can start building!

About the septic design, our Septic guy was very adamant about only designing CONVENTIONAL PRESSURE DOSE SYSTEMS - NO AEROBIC SYSTEMS!!!!! He says that big builders always put in aerobic systems, and they are high maintenance and costly because with aerobic systems you have to sign a maintenance contract with a septic guy that LINES their pockets. They basically want you to buy aerobic systems because they get so much in maintenance agreements. But here's what happens:
1. You have to pump out your aerobic system every 1-2 years. The holding tank for the aerobic system is so much smaller, so you have to pump more frequently (yuck!). The pump is used all the time, wasting energy and it wears out faster.
2. Sign an agreement with someone to do this maintenance, and if he dies, moves, or disappears, then you are screwed the money!
3. Aerobic systems don't last, but they are cheaper, so builders get it, but the homeowners are stuck with the maintenance costs and headache. Builders wash their hands of it after building completion.

Conventional Pressure Dose Systems:
1. They have much larger tanks, so you only need to pump every 5-6 years and have a much simpler design.
2. Pumps are only used when water is flushed, so since it is used so much less, they last up to 15 years.
3. You don't need to sign a maintenance agreement, and they don't require maintenance much. They are a few thousand dollars more expensive, so that's why more people/builders don't get this system, even though it is better quality, folks!

Septic costs (in Austin, Texas but they'll at least give you an idea!):
$14,500 - Septic total, 1250 gallon septic tank (for up 2800 sq. ft. home), using conventional pressure dose system, includes installation, materials, labor, design fee of $800 for septic engineer
$350 - Soil test drilling
$460 - Septic application approval fee (goes directly to Travis County)

TOTAL=$15,110

Here's a sketch of our septic design:

3 comments:

Anonymous said...

In NM, we can use bathroom sink, bath, and shower water as well as clothes washer water in the grey water system.

I have heard that many detergents have salts and phosphates that are not great for plants, though. Do you have any recommendations for detergents that are safe for plants?

------
Bob

Jan & Myleen said...

Hey Bob, yes, there is a great name brand called Seventh Generation that specifically says on its label that it is safe for graywater use and septic tanks. I read both their detergent and non-chlorine bleach labels just now :-).

Anonymous said...

Thanks! That's very helpful.

---
Bob