We have 5 children and my sister that lives with us. Our first leechfield failed after just 5 years. Now this one is going on 3 years and there are signs of this one failing as well. What is going on? All our contractor says is we have bad soils and none of the systems in this area last very long. HELP!!! Bonnie L.  

First, your contractors should be designing the systems in your area to deal with the problem soils. 

Second, keep in mind, when a properly designed septic system fails, they usually fail because they get plugged with solid materials that won't breakdown.

Gravel trench systems will usually last 15-25 years.

Graveless chamber systems, 10-15+ years.

Sand and peat filters, 10+ years.

Mound systems, 5-10+ years.

Aerobic systems, 5-10+ years.

HOWEVER!!! I have seen gravel systems fail in as little as 4 years and mound systems last 30+ years.

Get a certified septic system designer out to assess the site/soils and have them design a system that will work with what you have. 

Then start using that system properly and the way you make any system last longer is by keeping the solids out of the treatment media (drainfield) and you do that by using effluent and washing machine filters. If you use any system right it can last 100+ years.  Jim

I have read your site from top to bottom and found it to be the best source of septic system information available on the internet.  Thank you for making this knowledge accessible to all.  I do have one question however:  I see you state a septic system can last indefinitely, but then I read responses to people that they should replace their septic system.  Could you explain this.  Thank you.  Leonard C.   

First, the basic design of systems from 20, 30, 40+ years ago were woefully inadequate.  They were too small and too deep. 

Second, the materials used back then were not as durable as they are now.  Orangeburg pipe (oil-soaked cardboard or clay pipe used in the drainfield would easily collapse and the concrete used for the tanks was often a mix waiting to crumble. 

Third, people that used septic systems were never taught how to use those systems and abuse was the norm. 

Today we design systems that are sized to deal with the flows from the house and they are designed to treat that waste water.  We also use better materials, like PVC pipe and plastic chambers that will not collapse.  Tanks are made from a higher quality concrete or plastic composites. 

There is also the fact that people are learning how to use and maintain those systems.  Also research has pointed out one painfully obvious problem that causes septic system failure...septic systems fail when the soil/media treatment portion of the system gets plugged-up with solids that won't breakdown.  Now we know that if you want a system to last you can install filters in the tank and on the washing machine to keep these solids (particularly polyester and nylon) out of the soil/media. 

This is why a properly designed/installed system put in over the last 10-20 years with today's better materials AND used properly will last...Jim