Getting Your Septic Permit in Star Valley, WY: What You Need to Know

Alrighty everyone, this article is going to be a good one! Whether you're building your own home and need to know where to start, or you're building a home with us and just want to know what's going on, we're going to dive (pun definitely intended!) into the process for getting your septic permit in Star Valley, WY.

Fun stuff right? Well, maybe not too fun, but this is one of the most important aspects of your home: how we're moving sewage from the house, to somewhere that isn't in the house. We're going to run through the permit itself, some recent changes that are going to change the process a tad, all about your Perc Test, the different septic systems available, and some pricing information.

Buckle up, this article is going to be everything you may or may not have wanted to know about your septic system!

What is a septic system, and what does it do?

In areas of the United States where community a sewage system is not available, we have to invest in a "small wastewater facility" or septic system. This system doesn't treat your wastewater in the way a bigger city would deal with their waste, but it does separate the liquids from the solids and discharges the water into the surrounding soil. The solids are left in a tank, where it is later pumped out by a third-party pumping company.

This whole system starts with the sub-grade plumbing in your home, before you even think about toilets, showers, sinks, etc. Your main drain and waste vent (or, DWV) is responsible for containing all the grey and black water from your home and transporting it into a large storage tank. The solids sink to the bottom of the tank, and the liquids slowly drain out of the top into a replacement field.

What is a replacement field? Simply put, the "scum" layer of water from your septic tank flows out of the tank into a series of pipes or chambers, is lightly filtered (depending on the type of system it could be heavily filtered), and percolates back into the surrounding soil.

Your replacement field is doing the brundt of the work in this small waste water facility. That dirty water that siphoned off the top runs out into the replacement field which has the job of allowing the wastewater to seep back into the soil (don't worry, this is carefully engineered, but we'll get to that in a bit) at a rate that allows the water to drain but not flow too fast.

A traditional perforated pipe trench system. The septic tank is directly behind, out of the shot.

Obtaining a septic permit in Star Valley, WY?

Because this system is dealing with raw waste from your home, there are understandably some rules to how they must be constructed and where they can be constructed; this is all covered in the Lincoln County Planning & Zoning Small Wastewater Facility Application. This application does a great job of listing out the requirements needed to secure a permit, and walks you through the types of systems (which we'll cover in depth), and most importantly, how to perform a Perc Test.

Note that as of 2025, the Lincoln County Planning and Zoning handles all new small wastewater facility requests. We've just been told that going forward into the future, the Town of Star Valley Ranch will start to handle all it's own small wastewater facility requests. As this process unfolds with the Town, I'll come back to edit and update this article.

Filling out your Septic Permit

If you're building with Unshakeable Custom Homes, we handle all of this paperwork early on in the process during Pre-Construction (including the critical site plan that you'll need to continue this process). We work with you to fill out and sign the needed paperwork and submit this on your behalf. But generally, before we even start building, we have to have a "Pre-Application Soil Cut". The excavator comes out to the property and digs an approximately 8' long by 8-10' deep cut into the earth. It's then scheduled to have Lincoln County Planning Inspectors to come and take a look at the cut in the soil to ensure there isn't anything obvious that will affect the proposed placament of your septic facility. This is an inter-office thing that they do, so all we have to have prepared is the cut itself.

Once we get the approval from the soil cut, our next step is the Perc Test.

The Infamous Perc Test

A Perc Test, or Percolation Test, looks confusing at the outset but don't worry, it's not as bad as they make it look on paper! But what is a Perc Test, and why is it important?

The Prec Test, basically tells you (if you've done it correctly), the recharge rate of the soil in which you plan on placing a septic system. It's very important, mostly because undersizing your septic system can have disasterous consequences. Using the specific formula found on page 8 of the Lincoln County Planning & Zoning Small Waste Water Facility Permit, we're trying to figure out how fast, or slow, water drains in the area in which your conduct the test (which should be where you plan on placing the system).

Many jurisdictions perform this test themselves (mostly for consistentcy and accuracy), but because of the large land area and lack of inspectors in Star Valley, WY, the Planning & Zoning Office leaves it up to the homeowners and builders.

The Perc Test involves a series of 3-6 holes, evenly spaced out over the area of your proposed replacement field, that are used to get data on the rate of recharge into the soil. The data gathered from this test is used to then get the size of your replacement field and the length of your drain runs.

A sample Perc Test with the rates of drainage in the holes dug for the test.

Once we have the data from the Perc Test, we have the rest of the information we need to pick the type of system and the size of the system.

Choosing your Tank Type

The two main types of septic tank materials we see used around here are concrete and plastic, or poly. For the ease of this article, and mostly personal experience, we choose a concrete two chambered septic tank 99% of the time.

Because we have a high water table in many parts of Star Valley, WY, we opt for the concrete because we have heard of instances (and our excavator has seen it happen) where a plastic tank will "float" when the buoyancy from the high water table simply pushes it right out of the ground. Because concrete tanks have a huge weight associated with them, you don't ever have to worry about this happening.

Choosing your Septic System

There are two main types of septic systems that we choose to install here in Star Valley, WY: traditional perforated pipe beds and Presby systems.

Perforated Pipe Bed System

In a traditional perforated pipe bed, the replacement field square footage is found (using the information from the above Perc Test) and a "bed" is dug to match that square footage. Before any pipe is installed, a layer of sand and gravel is installed as the bedding layer, in which pipe is laid on top of that. The pipe is then covered with a specified depth of gravel, landscape fabric is laid on top, and then backfilled over.

A traditional perforated pipe bed septic system layout.

The obvious pro to this system is cost. Because rigid perforated pipe is cheap (a typical system can be done for a little as $2000-$3000 in pipe and fittings, plus the cost of the tank and labor to install), this significantly lowers the overall cost of the system. Another pro is ease of installation. Perforated pipe doesn't require any specialized tools other than an excavator to dig the bed. The pipe itself installs quickly with some labor.

A con to this system is the size requirements. A traditional bedding system require a large footprint, which can cause problems mainly in Star Valley Ranch, WY, where the lot sizes are smaller and therefore becomes tougher to fit in with a house and garage. You have to remember that nothing permanent can be built on top of your replacement field, so this replacement field area can really only be used as yard space.

Presby Septic Systems

Presby systems have been around for a number of years, but are gaining in popularity mostly because of the decrease in the system square footage and the way it treats the waste water. This system used a series of sealed chambers which keeps the inevitable small solids from clogging up a traditional system.

Another benefit is the smaller replacement field area required as compared to a traditional system. There's also some areas where only a Presby system will work, such as steep lots, or soil conditions where water is draining too fast for a traditional system.

The con (depending on how you want to look at it) is the cost. The last system we priced out came out to be ~$15,000 just in materials, not including the tank or labor to install the system. There are also very specific bedding requirements, such as specific depths of sand needed and specialized tools to connect the system together.

Moving Forward

So let's climb out of the weeds for a bit. That was a lot of information that you may or may not have wanted to know, but just remember that a septic system is an incredibly important part of the overall health and performance of your home. Once that system is installed and backfilled, we don't ever want to dig it up!

Before I sign off, I mentioned earlier about the Town of Star Valley Ranch adopting it's own septic inspection and application process. I've also heard talk of making chambered and Presby systems mandatory, although we havent heard anything concrete yet.

For most of you building with us, you'll sign the permit application and that's the last you'll ever hear about your septic system. But we believe it's our duty to educate our clients about the systems involved in their home.

If you have more questions about septic systems, have other questions about how we build homes, or want to schedule a time to talk, reach out. We're here to not only build homes, but to educate potential homeowners about the building process to help them make more informed decisions.