Can heavy snowmelt explain septic system failure?

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samiam1955

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We live in northeastern Mass. We had a whole new septic system in 2003, put in by a reputable company. 1500 gal tank for 5 people, now 2. No dishwasher, no garbage disposal. We are careful what we put down the drain, and have the tank pumped regularly. Last year (2015) we noticed the ground was a little wet in the leach field. This year (2016) there was standing water, so we had the system examined. They pumped out the lines, ran cameras down them, and determined the system had 'failed'. The biomat was not decomposing as it should, so the holes at 5 and 7 o'clock were all blocked. They put five bottles of a scrub in the lines and said, fingers crossed, that should break up the biomat with time.

This system should not have failed. What happened?

In February 2015 we had about 80 inches of snow, and a total of well over 100 for the winter. It didn't melt until mid-April. Could the overload of water from the snowmelt have saturated the field for so long that the biomat built up and caused the system to fail?
 
Traditional septic system or is it an alternative? Did they do soil testing before installation?
 
I guess it's a traditional system. It was state of the art in 2003, and met all Mass. Title V requirements. They did a perc test before installation. The field actually had to be one foot higher that normal (5' above undisturbed soil instead of 4') because it perked so fast.
The guy who scrubbed the lines said he could either jet the lines or scrub them, but there was no point in doing both. If the scrub works, there's not need to jet them.
 
State of the art in 2003, does not sound traditional. Is it just a tank and field or do you have pumps, floats, control panel, blower, etc.
 
What vegetation Do you have around your drain field? When you are referencing biomat, is this something that they installed or are you referring to the vegetation growing over the lines?
 
There is a 1500 gal tank, and a 20x30 drain field with three lines. There was enough slope from the tank to the D-box that a pump wasn't needed. No floats, control panel, blower, or filter. But every inspection of the tank has come up clean. We've had the tank pumped and inspected at least every two years. From what I've been reading, that is more often than is needed for only two people with this size tank.

The drain field is elevated up to 6' above original grade. There are some maple trees at original ground level shading it, but it's high enough up that the roots couldn't have grown up to the field in 13 years. Plus, the guy told me hardwood trees tend to send their roots down, not horizontally. The only vegetation over the field is grass, and the heaviest thing on it has been me with a push lawn mower. There's a crabapple tree near where the line goes from the tank to the D-box, and I found a few 1/2" roots when digging up the D-box, but the camera inspection didn't see any roots in the field.

By biomat, I'm referring to the slimy stuff that grows when there is insufficient oxygen and only anaerobic bacteria can grow. From everything I've read, I think the guy is right that that's what happened. The mystery is what caused the oxygen starvation, and the Winter From Hell is the best answer I can come up with.
 
I'll disagree with the fella on the hard woods. Rule of thumb is what you see above is what you have below. Pines sent a tap root deep down. Hard woods roots will go out a little farther than their branches and down a good bit depending on the soil conditions. Lack of oxygen could be your good bacteria in the tank was off or being pumped out too often. The bacteria that you need in your tank needs to populate and grow to do its job. It's been a while but I thought the good bacteria put off the oxygen in the tank when they consume their favorite meal. Some one is going to have to help me on this one. Septic systems are not my strong area and I don't want to steer you wrong. You shouldn't have to get your tank pumped unless you have a problem though.
 
Before we had the problem diagnosed, I was worrying because it's been two and a half years since it was pumped. So pumping too often is not the problem.
 
My limited understanding of septic systems follows.

There will always be a certain amount of solids coming from the house that the bacteria in the tank can not digest and liquefy. These will fall to the bottom of the tank, and the liquid will continue on to the drainfield. If these solids build up to the point that they are washed into the drainfield, they will clog up the drainfield, so that it will not longer be able to absorb the liquids. Therefore, it is necessary to get the solids pumped out of the tank every so often. It seems as though the OP has done this.

The biomat issue is one that I have heard of, but I don't really have a good grasp of what biomat is, what it's beneficial and negative aspects are in regards to a drainfield, and how to keep it at a healthy level.
 
samiam1955 said:
Thanks.

Is there something you think I'm missing? Or is a Penn State article a no-no for a WV guy? :D
Click to expand...

Your article is just one opinion/view.

You need (IMO) to search more sources of info.

For example- (This excerpt was from the URL I referred to in my first post).

The septic system bio-mat: this article explains the formation of the bio-mat below septic drain field trenches and around cesspools and some dry-wells and explains what the biomat does.

The bio mat, a bacterial slime layer in the soil below the leach-field and around other wastewater disposal systems, is a critical component of private septic systems - it is responsible for treatment and reduction of biological solids and pathogens in septic wastewater effluent which is discharged into the soil from a septic tank. The most common and most expensive failure of private systems occurs as soil clogging and failure of the absorption system to continue to accept water.
Click to expand...

It is formed and is there. A properly functioning system will not allow a massive build-up of bio-mat.

Please note that I am not a professional but after my septic failure educated myself somewhat. You will hear all kinds of reasoning and suggestions as there seems to be no set repair procedure(s). There are methods/options to hopefully reduce the bio-mat before spending the big bucks for a new field.
 
frodo said:
how deep is your drain field ?
how deep is your frost/freeze line ?

if your drain field is frozen it will not perc
Click to expand...

I think the drain field is 2' deep. It was built in 2003 and went through 11 Massachusetts winters with no problem. The design codes here must account for the frost line in our area. The first sign of a problem was after the winter of 2014-15, when we had record breaking snow. If anything, the 80 inches of snow that stayed on top of the drain field for an extended period would have insulated the drain field. The frost goes much deeper in a winter with less snow.

Thanks for all the tips. I still think the melt from the 100 inches of snow overwhelmed the system and caused the biomat to build up beyond normal. I was wondering if anyone else with a septic system in New England had problems like mine after that winter.
 
samiam1955 said:
I think the drain field is 2' deep. It was built in 2003 and went through 11 Massachusetts winters with no problem. The design codes here must account for the frost line in our area. The first sign of a problem was after the winter of 2014-15, when we had record breaking snow. If anything, the 80 inches of snow that stayed on top of the drain field for an extended period would have insulated the drain field. The frost goes much deeper in a winter with less snow.

Thanks for all the tips. I still think the melt from the 100 inches of snow overwhelmed the system and caused the biomat to build up beyond normal. I was wondering if anyone else with a septic system in New England had problems like mine after that winter.
Click to expand...

if the snow pack, and melt is the problem grade the yard so the melt will run away from the drain field.
 
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