AAA Home Drainage » drywells perk

Myths that sump pump installers promote about home drainage

DL — Tue, 22 Dec 2009 13:11:14 +0000

Underground rivers and springs under your home? Not very likely. This is such a common statement however, that is over and over again thrown at homeowners by sump pump installers.

You know that old story. I am sure you have heard it many times.

Neighborhoods with no professional home drainage systems installed, such a hand excavated french drains, are often the best misinformation tools the sump pump installer has, because he has the seeds of that story already planted in those homeowners who just sump pump forever, knowing that the underground spring or river is forever. That is just not true.

What a load of horse pucky. My spell checker loved that word, pucky. It is still is beeping. Never the less, it fits the moment.

You know the old story. The one about underground rivers and springs under your home, which is, in conjuction with that statement, a segue right into the sump pump installers requirement to excavate the crawl space, install a sump pump somewhere, and basically run wild on your property for a little while, making away with your cash in the end.
All at a cost that provides absolutely minimum to zero home drainage help in nearly all cases. Sump pumps do not prevent groundwater from running below grade in crawl spaces or basements.

The homeowners belief in this story has been the sump pump installers go to bread basket and anxiety producing tool, used to worm money from misinformed and fearful homeowners confronted during a home sale with the fact that the home has a drainage problem.

Cities and counties do not often drop the ball and allow building in flood zones or zones with underground springs near the surface. They do not miss low areas.
All professional home drainage students and contractors who didn’t miss class know that the springs and underground rivers story is just a bunch of bunk.
It is the most common statement I hear from homeowners however, next to the fact that they contend that the water table is high, which is another misunderstood concept.

Ask the sump pump guy, why, if there are underground rivers and springs under your home, like he says, and a permanent source of groundwater under your home has likely existed under your home from day one, like he says, right under your home; and the groundwater problem is not a hard rain caused problem that should be dealt with on the outside of the home, and not right against the foundation wall either; if this is true, why are those springs and rivers not running in the summer, or any other time other than winter when everything is already saturated from rain water on the surface and groundwater has not been removed from the foundation area with hand excavated french drains.

No groundwater removal on the surface levels of the ground around the foundation equals saturation, equals hydrostatic pressure, equals groundwater entry below grade into the crawl space or basement.

The reality of the discovery of home drainage problems almost always has nothing to do with stories of underground rivers and springs.

Subdivisions are platted after consulting U.S. Geological survey maps, geo-tech studies, on site evaluations, permit approvals which contain drainage and geo-technical data as part of the feasibility study and the developers list of conditions of approval for the subdivision, and other siting information that determines the non-buildable status of a parcel of residential zoned land.

Seldom do subdivisions escape the permit process due diligence. Lots with steep topography and low groundwater areas are given common area status within the subdivision and are not platted as buildable lots.

Your land may have developed a true spring after the home was built, perhaps years later, but even a true spring, by definition, is fed in quantity by rains, and totally controlled in volume by the rain amount and intensity.

Seldom are any springs actually year round. When they are year round clean springs, they are worth lots of money, just to bottle these days for drinking water.
So are those trickles of water in your crawl space or basement actually springs? If I cut off the source of groundwater feeding them from above, with hand excavated french drains, will the springs just dry up? Yes they will.
The percentage of home drainage problems that still require the sump pumping of groundwater is very small, after grade enhancement and compacting at the foundation and after the professional installation of hand excavated french drains has been completed.

When installing hand excavated french drains during the winters worst saturation, be patient looking for fast complete results. You cannot just turn off the groundwater like it was on a switch once the ground is saturated. The groundwater removal begins right away.

The results are noticed days to weeks later, due to groundwater saturation and a smaller degree of hydrostatic pressure that still remains along the foundation, until a summers warmth has dried the homes foundation area and crawl areas, and a new winter seasons rains can be vented away rather than let saturate next to the foundation.

In terms of geology, how does groundwater perk

DL — Tue, 03 Nov 2009 00:27:40 +0000

What does it mean when a geologist uses the term to “perk”. This term describes a process that soaks groundwater from the surface of the earth, into the aqua layers containing our underground water storage caverns.

What is a perk test, and what does it mean in terms of home drainage and groundwater removal?

How does the term “perk”, apply to hand excavated french drains?

Many homeowners who have built a home on a parcel of land that was not in an approved subdivision will likely recognize the term, “perk”.
When a prospective buyer of a parcel of land makes an offer, via an earnest money agreement, a contingency of the offer should say that the purchase of the land is subject to a satisfactory perk test prior to closing escrow on the land.

This contingency protects the buyer from losing money on a property that can not have a home built in a conventional manner. If the buyers were to pay cash for the land, for instance, and the parcel could not pass a perk test, they would own a property that would not be able to get a building permit to build a home with a standard septic approval and septic tank/drainage field system.

The septic tank and drain field soaks the homes household use water and sewage into the ground.

Let’s get into the nuts and bolts of this process. The building department instructs the plumbing department within the zoning planning department of the city or county, or the sewer office, to have a large hole dug with a backhoe on the property in the area of the proposed septic tank and drain field. The hole is most likely 4-6 feet deep, and about that wide. The test hole is filled with water from a water truck in most cases.

The plumbing inspector comes back in a few weeks, and if the water has started to soak out significantly, or is completely gone, the buyer will most likely get a standard septic approval, which will be used in the closing and home loan process to remove the perk test contingency and serve to notify the lender, that the home can be built with respect to that issue. In that case, you have just passed your perk test.

A hand excavated dry well is a groundwater mitigation area, that to begin with, holds the groundwater that is sloped to it by the hand excavated french drains. When the groundwater perks into the soil, even hard clay usually perks, it makes cracks on the bottom of the hand excavated dry well.
Hard clay just takes a little longer to start the perking, but shrinks very well, which makes large cracks that make for great hand excavated french drains and dry wells.

Each time the groundwater is collected into the dry well with the french drains, when it rains, the groundwater soaks out quicker than it had previously, due to the cracks in the soil, on the bottom of the dry well, that were already formed during the former perk on the bottom of the hand excavated dry well.

Cracks in the clay and soil dry well bottom, formed on the bottom of the hand excavated dry well from groundwater perking, as a result of the perk process, get larger as the wet and dry periods come and go, and the soil or clay shrinks, making the cracks wider.
The same result occurs if you pond an area, and then let it go completely dry. You will see a checkerboard area of cracks on the surface, and in the summer when the ground is very dry, you could lay a hose down and watch the water soak into the ground as fast as the hose will run, in most cases. Do this test and you will see.

That is why lakes, ponds show cracking when they are flooded, and then go completely dry. Our planet is constantly perking groundwater to the middle earth water caverns we drink from in the end.

So, that’s it hand excavated french drain and dry well fans. That is why your dry wells work. The groundwater doesn’t stand in one place through the lineal length of your hand excavated french drain, located around 18″from your foundation wall, in most cases, because of the slope that is created on the bottom of the hand excavated french drain, so groundwater does not pool and soak in there, and therefore does not form the large cracks in the dirt and clay that soak out groundwater like the hand excavated dry wells do.

The average hand excavated drywells, used for residential purposes, depending, of course, on the overall size of the home and whether the rain drains for the home are included in the drainage plan, should be approximately 4 feet in diameter by 4 feet deep, and be free of all loose dirt or clay, so a mushy mud does not form on the bottom of the dry well.

A drywell can be excavated by a machine for commercial applications if all debris is cleaned and straight sides and a flat bottom can be accomplished, but drywells of larger than 4 feet deep are not OHSA approved for safety of workers doing hand finish work, without a supporting structure to hold the sides out, preventing a cave in during construction that would injure or kill workers.
Many times rural farms will use the same type of groundwater removal system, on an enlarged, and machine excavated scale, but the hand excavated french drains used to collect the groundwater around the barns are created in the same manner as for residential in most cases.
I installed hundreds of lineal feet of hand excavated french drains for the Columbia County Fairgrounds St. Helens, Oregon in 2007, where the cow and horse barns were flooded with manure and groundwater from the roof rain run off and bad topography.

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