Dead grass in drainfield

[doots]

Been in a new house less than a year and recently noticed a pattern of dead grass over the drainfield that seems to follow the pipes. This is new as of the past couple weeks, and follows a period of warm weather followed by maybe a week of rain. Picture attached.

We have not noticed any problems with the septic system operation.

Should the dead grass be at all concerning?

 

[kappitts]

What kind of system do you have? Is there any form of disinfection?

Most of the time the drainfield lines are marked by lusher and greener grass. From time to time there is a system that has only dead grass over the drainfield lines. Usually shallow gravelless trenches have dead grass above them.

 

[doots]

Thanks for the reply. Had to go find the as-built, sorry for the delay.

It is a Sandfilter LPD design. The as-built calls out:

810 sq ft drainfield
270 L.F. trench
14" deep trench
36" wide trench

And the drawing of the drainfield seems to match the patterns of dead grass, so those are definitely occurring over the drainfield lines.

I don't know of any disinfection. We haven't done anything to the system in the year we've been here and the dead grass patterns just appeared recently - could that suggest something we put down the drain could be hurting the grass?

Thanks

 

[Chris]

Either that or there is a possibility they are very shallow and the dirt between the two is drying out killing the grass. Does it get plenty of water?

 

[doots]

I don't water it, so it could be that it is drying out. There was a span of hot weather a bit before I noticed the dead grass but it was followed by a week or so of rain, and I'm not really sure if the dead grass appeared before those rains or not.

But I'm mostly worried about whether this could suggest something wrong with the system. It was pumped about a year ago, before we moved in. Would it be appropriate to get it pumped just to be safe, or to have some other sort of checkup done on the system?

 

[Chris]

Pumping your septic tank will do nothing for your leach lines. Really you would need quiet a bit of water use in your home to even saturate the leach line dirt. It will take hundreds of gallons or more to get everything wet unless you have soil that doesn't perk. Those lines are just air voids under ground to create a space for water if needed and are always overkill for what you actually need. Say if they are lees than a foot deep then it would not be hard for the dirt on top to dry out, the water will perk down to the leach line pipe or chamber and run down to the bottom of that creating less moisture retention than solid dirt.

I would keep an eye on it for a while and make sure you keep that dirt moist and see if grass starts growing back.

How many people in the home? If one or two that could be the reason it gets dry.

 

[doots]

Two adults and a child in the house, and the system is set up for a 4 bedroom house. I'll try to water the area a bit to see if it helps.

Thanks for the feedback.

 

[kappitts]

LPD: low pressure drainfield. It sounds like you have a shallow gravelless trench system. This system is designed to force the effluent to drain downward. This means the effluent will not water the grass. Also, the trench is quite shallow and the plastic cover is probably 6-8 inches wide. Warm effluent sprays out of the lateral and hits the half pipe covering, also, the sun warms the shallow dirt above the half pipe. This creates an area that is very unfriendly to grass. View attachment ImageUploadedByPlumbing Forum1442494891.646865.jpgView attachment ImageUploadedByPlumbing Forum1442494905.748827.jpg

 

[doots]

Thanks kappitts, it sounds like I shouldn't be too surprised at the dead grass.