Drywell, what is it?

[JC4HD]

Looking at recent posts on septic systems and a drywell was mentioned as a better way to handle (Gray Water) what exactly is a drywell and how does it work?

 

[chim]

I remember my Grandad having one put in the back yard for the washing machine water. It was a hole in the ground with block walls and a concrete cap, then covered with dirt and seeded. Gray water was directed into it and it seeped iinto the ground. They told me at the time it was a dry well.......................chim

 

[Steven]

They are holes dug and filled with crushed stone to take up water. I have them on the down spouts of the house to take the rain and put it into the ground away from the house. they also can be used for grey water whitch contains no sewage so you do not over use the septic system.

 

[benewton]

As done around here...

Our dry well is, essentially, the cesspool portion of the septic system without the bottom, if you know what I mean. Basically, a concrete cylinder with neither top nor bottom.

It is filled with rock, and your gray water outlet is vented into it. Not for toilet waste, nor, I think, ditchen sink, garbage disposal, etc.

Once filled, it was covered with light tin, then dirt.

My reason was simple: my boss likes to use bleach, which, as we all know, is a fairly powerful antiseptic, and the little guys in the septic tank didn't like it at ALL.

Anyway, so far, so good: the septic field seems to have come back, and she's still alive.

 

[RJohnson]

Jim
I think chim has pretty well summed it up. Dry wells are also known as seepage pits and cesspools. They are now outlawed for septic use (black water) and are constructed of open-jointed walls (concrete block or stone) and open bottoms. They are still used in some areas of the country for grey water. The problem that I see with dry wells is that grey water can be just as hazardous as black water. Grey water can carry virus and bacteria and could cause problems if you have a high water table for the grey water to seep into before it can be "treated" by the soil bacteria. The other problem is that nitrogen and phosphorus from washing machine detergents are becoming more of a pollutant. A dry well does not contain enough organic matter to allow bacteria to live and digest the grey water well so it usually passes into the water table with very little treatment. I would rather run the grey water with the black water into the septic tank.

Randy

 

[MarkV]

Randy has some good points. You need to check before you install the traditional gray water dry well. In this area they have been out lawed for fear of what affect they have on the aquifer.

MarkV

 

[JC4HD]

My planned usage would be for sink water only... no garbage disposal, just dishwater. This is a camp that we visit maybe two weekends a month... usually just me a the wife! Currently after the dishes are washed.... the "dirty"water is carried about 40 feet and dumped... then the dishes are rinsed and the rinse water is dumped... it seems to me that a drywell would do the trick if placed down hill from the pump well which is outside the cabin.
Opinions?

 

[Inspector507]

I was wondering.........what if it were just the sump pump discharge that went in a dry well? It is ruining the yard where it discharges now.

Jerry

 

[Will_C]

Just to add to some ggod points made about drywells. In many areas of the country, grey water must be trated the same as black water, going into a septic tank first. It is possible in some areas to buy a pre-cast drywell that is essentially a septic tank with drainage holes cut in. If you are planning to use a drywell, stone or gravel should surrond it, and if it is going to get heavy use, the native ground should also allow for good percolation of liquid. If legal, a drywell does sound like a good option for a camp type dwelling.

 

[MarkV]

Jim,
For the amount of use the camp dry well would get old timers would often use a 55 gal drum. Standard drum would be punched full of holes, buried and filled inside as well as around the exterior with something like #4 gravel. Of course you need to run your drainpipe into the drum before filling. I would also think adding a liner of fabric to the hole, like silt fence fabric,to isolate the dirt from the stone would be a good idea. If you can do it in your area it would be cheap and simple as well as much easier than hauling the water to the woods. Might not hurt to use a biologically safe soap at the sink but I would be surprised if normal use would effect the well unless it is very shallow.

MarkV