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Septic Test Hole Application in Idaho

Septic Test Hole Application in Middleton, Idaho

Hey everyone, Brian Freeman here. Today, we will look at an application for a new septic system. This application is for Middleton, Idaho, which is in Canyon County. The jurisdiction is Southwest District Health. I want to review with you a septic test hole application and why you need to get it done. Then we’ll talk about a septic as-built such as how you can get one and use it.

Is a Septic Test Hole Application for New or Existing Homes?

You can apply for a septic hole test if you’re buying a home and want to know where your existing system is. You can also apply if you’re buying vacant land and need a new septic system.

Permit for a Subsurface Sewage Disposal System with Southwest District Health

We’re looking at an application for a new septic system on the property, and the permit is for a subsurface sewage disposal system with Southwest District Health. Each city will have a potentially different jurisdiction, but Middleton is in the Southwest District Health. Each permit will include a permit number at the top, date, parcel number, property address, and the applicant’s name.

How to Determine the Leach Field and Septic System Requirements

Once the health department reviews the property to determine whether the soils are acceptable, they will provide us with the requirements for the leach field, such as the size and type, as well as the septic tank size for the number of bedrooms that will be in the new home.

What is an As-Built Septic System?

Once a septic system is built and installed, you can request records of the septic as-built from the health department, in this instance, the Southwest District Health, which determines the location of the existing septic system on your property. You can also access test results and determine if the original owner never pulled permits.

Why is an As-Built Helpful When Building a New Home?

If I want to build a barn, horse corral, or maybe an arena in a particular area, you don’t want that on top of your septic systems. So you must ensure you can do what you want with your property by knowing where your septic system is. So that’s why you want to get an as-built if you’re buying a new home. If you need a new septic system, you will also want to request an as-built.

Know the Source of Your Water Before Installing a Septic System

The application we are talking about references the size of the property, which is 2.65 acres, and the type of installation they’re applying for is a new basic system with a gravel field drain. They’re also applying for a private water supply due to no city water access for the home’s location. So you have to drill a water well and get that to source your water. So it’s imperative to know your water source because water wells need a hundred-foot setback from any septic system; you must ensure that the well can go a hundred feet away from that and a hundred-foot radius.

Conditions of Approval

They excavated the system we’re referencing to be 24 inches to 40 inches deep. In addition, they installed a gravel drain field per technical guidance manual specifications to ensure a 100-foot setback back to all water wells and a 50-foot setback to the seasonal ditch.

Seasonal Ditch Specification

This lot has a seasonal ditch. It runs off from a farmer’s field, so they only require a 50-foot setback. So we’ll look at a couple of other options for actual water on the property and the setbacks as they increase a hundred and even 200 feet away from that, which limits where you put your septic system, especially on smaller parcels.

What Causes a Drain Field to Increase for a Septic System?

They’re applying for a five-bedroom residential permit. The drain field will increase based on the size of the number of bedrooms, not the bathrooms. Then they calculate the average gallons per day, which is 350 gallons per day in this case.

B2 Soil Type

The parcel we’re talking about has a soil type of B2. It’s not the best soil, but it would work with a decent system. As the soil gets worse, we mean that it doesn’t leach, and it doesn’t absorb the water or the affluent as well. It will increase the size or square footage requirement for the leech area, which is the drain bed.

Septic Tank Capacity

This home will require at least a 1,250-gallon tank, which is also based on bedroom size. So a two or three bedroom would not be necessary to have that total 1,250-gallon tank.

Septic System Drain Field Size

The actual drain field size is 778 square feet. So you would figure out how they want the system designed. For example, if it’s a six-foot-wide trench that goes a hundred feet, you will figure out how many have a six-foot separation between them. How many trenches will that be? And how long are the trenches? You have to end up with 778 square feet of drain area.

Setback from a Permanent Intermittent Surface Water

The property we’re talking about has a drain field with no closer to permanent intermittent surface water than 200 feet. So that would be a pond or other permanent water source. So that’s the setback; it can be very significant.

How to Get Approved for a New Septic System and the Costs

All you need to do to get approved for a septic system is to contact the health department, create the septic test hole application, and pay them about $400 or so. At that point, the inspector would come out to inspect the site to meet with you and the excavator, and then the excavator digs the test hole that allows you to determine your soil type. After the test is completed, you are approved, you decide to move forward, and you’ll apply for the permit. The cost to do that is roughly $400. 

You’re up to $800 or $900 in total, which gives you what you’ll need to get a new system, and the inspections to get the new system approved and installed. Getting your septic system permit pulled should be done with your building permit.

Start with the Soil Type for a Septic Hole Test

The starting point of the test tool is the soil type; the soil type for this parcel is B2. The inspector will pick up the soil in his hand and move it around, which he does as he goes along his inspection. He then takes notes as the hole is dug. For example, the inspector of this parcel said it’s fine, silty, topsoil, black, and dry. Then 3 feet down, you have a B2, soil, red and brown, fine, silts gritty, little sand, and mild compaction. And 7 feet down to the test hole, it’s more sandy. Its soils are B1 which is getting better, so you get into the A’s, which are excellent soils. Then it goes to eight feet, which is where they stop. So they were happy with the soil.

Breaking Through to Good Soil

Let’s say you hit the hardpan hard or you’re hitting lava; they’ll make you break through that and go down further until you get to good soils underneath. Then you would over excavate down 10 to 12 feet and backfill up to four feet with sand, giving a good bed for the drain so it can leach down. This test hole is dug to know what the soil is like. So that’s why the inspector comes out to do this. Lava could be two to four feet. And even if you hit hardpans rock, you have to break through that too.

Dry Ditch Setback

The property has a road, an old house, a driveway, and a dry ditch. The dry ditch is required to have a 50-foot setback. It’s essentially seasonal water runoff from the farmer’s field.

Locating Test Holes with GPS Coordinates

The TH stands for test hole, which they reference on the newer test and was completed in 2018. They will get GPS coordinates so you can see a GPS coordinate that will reference back to exactly where the test hole is. They typically like you to be within about 50 feet of that test tool. Otherwise, you’ll have to do a new test. A new test would require you to reorder the test and pay to have them back; this is pretty typical. You can also see the North orientation of the lot.

Do You Need a Building Permit for a Septic Permit?

To complete the application, you’ll need to include a submitted plot plan and zoning documentation. The Southwest Health District wants the building plan submitted and a plot plan approved. So they’re not going to issue a septic permit without a building permit, which is essential.

Setbacks for Surface Groundwater and Water Wells

The soil type is B2. If there is permanent surface water, you must be 200 feet away from it—for temporary surface water, you will need to be 100 feet or greater to avoid groundwater issues. 

If you have no groundwater issues, the nearest water wells must be 100 feet, or more, away from the septic system leach field.

Septic Systems and As-builts for Homes and Parcels of Land

If you’re applying for a new septic system on vacant land or a second dwelling, you will have to go through the health department, Southwest District Health, in this instance, in Middleton, Idaho. Make sure you’re checking for an as-built too. If you’re buying a new lot, or a home that’s already existing and has an existing system, you want to know where your septic system is located to ensure you don’t build anything on top of it. Make sure you know you can build what you want on your property.

What Happens if the Property Does Not Have Good Soil?

If you get on property that does not have good soil, it could increase the size of the septic system you’re required to install. Occasionally, you have high groundwater during the tests, which could need you to build a mound up and have a higher pump system to raise the system above the water.

How Much Does a Pump System Cost for a Septic System?

Pump systems can be costly depending on what kind of system and the size of septic system you’re required to install, ranging in costs from $20,000 to $50,000.

When Do You Apply for a Septic Hole Test?

You want to get these tests done on the front end if you’re purchasing land. Ensure you do it during the due diligence period in escrow before your inspection periods expire. That way, you can eliminate any real big surprises down the road.

Wrapping Up

I hope that was helpful to understand better the septic tests in Canyon County, specifically Middleton, Idaho, with the Southwest District Health. If you need help buying land or buying or selling a home, feel free to contact us. You can also listen to us on the Real Property show. It was great talking to you, have an excellent day.



1. Request a Project Consultation Online or by Phone

2. We Will Meet With You at Your Home or Building Site

3. Establish a Budget for the Project & Start Drawing Plans

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