The Percs of House Building

Last week some official initial site planning took place. A surveyor and my dad dug some deep holes for perc tests. I guess the process is to dig holes, pour in water, and time out how long it takes to drain. According to Wikipedia:

The goal of percolation testing is to ensure the soil is permeable enough for septic tank effluent to percolate away from the drain field, but fine grained enough to filter out pathogenic bacteria and viruses before they travel far enough to reach a water well or surface water supply. Coarse soils – sand and gravel – can transmit wastewater away from the drain field before pathogens are destroyed. Silt and clay effectively filter out pathogens but allow very limited wastewater flow rates. Percolation tests measure the rate at which clean water disperses through a disposal trench into the soil.

Apparently the results weren't ideal, but either way we were going to need to dig some deep trenches and have a Monroe County official come out and inspect the dirt, which was scheduled for today.

Prior to today, a few stars aligned. A neighbor who runs a deer farm visited my parents a couple weeks ago because a bunch of the deer got loose, and they were wondering whether my parents had seen any. My dad agreed to keep an eye out... and meanwhile, it turns out this neighbor has a backhoe/bulldozer, and is willing to help out with digging. Fantastic coincidence!

Today, the surveyor, the inspector, the neighbor, my dad, and Matt and I all met in the field to dig trenches and analyze the dirt profile. Water was poured into the perc holes again for the inspector to observe and time.

Perc test site 3 of 3

 And then our friendly neighbor started digging!

After digging about 4 feet, the inspector hopped in.

He picked away at the walls, crumbled the dirt in his hands, and measured how deep any mineral deposits were. Apparently minerals started appearing at about 19", which indicated the presence of water. The septic leach field needs to be a certain amount above the water table (I think 2'), so we would not be able to do a conventional below-surface design. Instead, we would have to do a modified raised system, which would be more expensive. Basically we would need sand, gravel, and topsoil to make up the depth difference - assuming the perc tests would pass within 45 minutes. However, it didn't look like that was going to happen. After digging down two more feet to make sure the analysis of this ditch was exhausted, the hole was backfilled and we scoped out another spot which might be more suitable.

Soil profile in the first ditch. The orange stripe is the mineral deposits.
The soil was rather sandy, with enough clay to be able to mold a ball.

As opposed to the initial dig, which was slightly downhill and west of the proposed house site, the surveyor suggested trying to dig east of the house where the land also sloped away, albeit more gently. And so, ditch #2 was dug.

This time, mineral deposits showed up at only 8" - even worse. We gave this ditch its due diligence and still dug down the full 6 feet before backfilling, but it was clear this site was not going to work. And after checking the perc tests, it became clear that in order to use the initial site, we would need an even deeper raised bed system - which would be even more expensive.

After the initial surprise and panic subsided, brainstorming ensued. So long as we were 100' away from any neighbors or streams (no problem), we could have the leach bed farther from the planned house site. We went back to the west side, further down the hill, and dug a third hole.

This dirt was rockier, but - success! The mineral deposits were 24" down this time. While we will likely still need to do a modified raised bed system (considering the slow perc tests), to install it further down the hill would mean trucking in less sand and topsoil. So it's looking like this will be the site.

Unfortunately, we would need new holes dug for perc tests to determine the necessary depth/height of the system, which would take more time than the surveyor had for today. We will have to wait until next week to get new perc tests done, and then have the inspector come out again and basically repeat the whole process we went through today - but hopefully next time we'll actually end up with an approved site.

Once we know where the septic is going to go, we can get a well drilled and house plans drawn up while the surveyor develops the detailed site plan. Although today did not totally go as planned, we have the time to be flexible and still keep on our rough timeline. Besides, it was fun getting out to the site and digging some holes - this is getting real! The not-so-fun real part was that today we incurred our first costs.

Gratuity to neighbor for use of his backhoe/bulldozer (initially he politely refused, but we wanted him to walk away with something): $60
Fee to Monroe County Dept. of Health: $125
Surveyor Fee: TBD with contract
Total spent thus far: $185