Septic System Failure! How to Rehabilitate a Failing Septic Leachfield

Summary: Simple, low cost measures to repair failing septic system or failing leachfield, in place.


Maybe you've already got raw effluent bubbling over the surface, maybe it's just threatening to.

Or perhaps your local authorities are simply asking that you do a $20,000 overhaul of your system.

Maybe you just want to save money and resources by doing the most effective septic system maintenance, and nothing unnecessary.


What to do?

Well, here's some strategies, in order of effectiveness:


Where does this information come from? What is our angle?

We are providers of original, accurate, up to date information on ecological living, since 1980. We don't sell septic system components, or do installations (except as part of R&D on new designs). We do wastewater system design, but we are probably too busy to take your project on. We give away about half of our info online, and sell the other half. What we get out of posting hundreds of pages of info for free is that some fraction of you will conclude that our free info is so helpful you'll link to us, which will increase our visitor traffic. Others will conclude that as much as our free information is helpful, buying a books or DVDs would help even more. Our main strategy to this end is to be accurate and trustworthy.


Here's those strategies—


Give the leachfield a rest by fixing leaks

The issue: The relentless, 24-7 nature of leaks prevents the leachfield from ever drying out, which can lead to progressive failure due to the growth of anaerobic biomats, which have about 1/100th the permeability of the soil they grow over.

The cure: Fix all leaks.

Give the leachfield a rest by diverting laundry greywater

The issue: Laundry greywater is about 20% of total septic loading, average. However, it does more harm to leachfields than water from any other fixture. This is because waterlogged lint from clothes is almost the exact density of water, so it is not removed by settling or floating in a septic tank, some of it just floats on through. Once at the soil interface, it tends to "paper mache" this interface shut, especially with non-biodegradable lint from synthetic clothes.

The cure: Re-route laundry greywater from the septic to mulch basins in the landscape, for irrigation or just disposal. Our Laundry to Landscape  page explains (free) how a handy person can do this in an afternoon, with all on the shelf components. It's also got a list of installers who can do it for you. Our Laundry to Landscape (DVD) gives in depth visuals on how to design and install a system.


Give the leachfield more of a rest by diverting the rest of the greywater

The issue: Greywater is 60-80% of total septic hydraulic loading, and about half the solids (mostly from the kitchen sink). The relationship between septic loading and failure is exponential. Reducing the load by half could extend the life not by twice, but by four times.

This can also work against you, if the load on a septic doubles, its life can be reduced to one quarter. This is not the exact mathematical relationship, but it gives you the idea: Taking water out of the system dramatically extends its life.

The cure: Re-route all greywater from the septic to the landscape, for irrigation or just disposal. Our Grey Water Central leads to about 100 pages of free info on this topic, and Create an Oasis with Grey Water (book) is the definitive work on this topic.

Conserve water

The issue: Same as above.

The cure: If you've already re-routed all the greywater, the only thing left to conserve is toilet flush water. You can do this withComposting toilets, and/ or ultra high efficiency toilets. For info on this and other approaches, see our Water Conservation Central.


Install a leachfield protector in the septic tank

The issue: When the space in the septic tank between the scum mat and sludge is too small, solids can get flushed into the leachfield.

The cure: A leachfield protector is a screen that you install on the outlet that clogs (cheap repair) instead of letting the leachfield get clogged (expensive repair).

Note that this is more in the nature of cheap insurance. It won't cure an already wrecked leachfield.


Pump the septic when necessary

The issue: Same as above.

The cure: Pump the solids out of the septic. You can do this on a schedule if you like to spend money unnecessarily; you can check the thickness of the scum mat and sludge layer, and have it pumped only when necessary if you want to spend just the right effort....and you can wait until the leachfield clogs and then pump the septic, if you want false savings...


Note that this is more in the nature of cheap insurance. It won't cure an already wrecked leachfield.


Install a leachfield extension or modification

If your leachfield has failed, install an extension or modification. For free ideas on improved green leachfield design, see:Green septic system.


Good luck!

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