If you’re looking to build on a new piece of land, evaluate a piece of land, or replace a current septic system, we have you covered! 

We handle all areas of the septic installation process. From evaluating the land, designing the system, handling the county permit process, and management of your septic construction.

If you’re in Pierce County or parts of King County, looking for a septic design engineer, give us a call today!

The Process of Septic System Design: From Empty Lot to a New Family Home

The entire process from finding the right lot to purchase, to having your dream home built, begins with the need of an engineer for septic tank design (that is, if city sewer isn’t nearby!). City and county laws have extensive building laws on the type of lot, the topography of the lot, and even the soil within the lot. So a major part of our job is handling all the bureaucracy! And trust us, you don’t want to deal with that part…

You may already have a piece of land or are looking for a piece of land to purchase. Either way, you’re wanting to build a home there.

So let us walk you through the entire septic tank system design process that’ll turn that empty piece of land to a livable family home!

  • Research the Land

    This requires looking up the County, city, and/or tax records for any information about the piece of land. Our goal is to get the history, topography, wetland info, or possible soil information.

  • On-Site Digging

    Here we create a deep hole for assessment purposes. Here we can diagnose soil type, depth, and any other conditions of the building site.

  • Land Evaluation

    During our same hole digging visit, we determine the viability of the piece of land. If we can confirm that it’s ok for adding a septic tank, then we will describe the type, size, and location for all the components of the system.

  • Septic System Design

    Based on the findings from the land evaluation, it is now our time to put our engineering skills to work! We create an extensive design showing the type, size, and location of the septic system on your property. This is very detailed, as required for the next step.

  • County Applications

    This is the fun stuff… not. The county requires the septic system design we created and an application to be filled out, which we completely handle! (this is also a good time to see if you can apply for a building permit as well!) The tough part here is that we’ll need other documentation such as Critical Area Determination, Water Supply Verification, and anything else that talks about the building site in question. After the application and all documents are put together, we can then send it to the County Health Department for review. Then, the county will send out a representative to check the soil themselves, we walk them out there and describe the findings and our design drawings.

    Unfortunately, this can be a long-drawn-out process. But we promise, we’re good at moving the county along 😉 and Pierce County has a great website with all the necessary septic information and allows you to track the status of your application.

  • Installation

    This is the fun stuff! Once the county finally approves of the septic system design and evaluation, you can obtain your building permit and lay the foundation to your new home down. Then, it’s time to hire a professional septic system installer (also needs to be licensed through the county). When we get to this point, we will have a list of potential companies that you can get bids and choose from.

    Once you choose an installer, they’ll contact us for a “stub-out release”. Here, we’ll need to get more documentation from you. These documents pertain to maintenance requirements, for septic and well, attached to the title of your property. Once we get these to the County, we can request that they release the installer permit to your chosen installer.

    Now the installer begins installing your new septic system. Once complete, we will meet with the County and the Installer, to make sure the new system checks out. At this point, we will create an AS-BUILT package of the septic tank design, for the final County review. Once approved, this property is now livable!

Types of Septic Systems


The basic septic tank and most common. Waste goes into the tank, solids separate to the bottom, where it degrades over time. The liquids flow out via gravity to a distribution box, where it is evenly distributed throughout the drain field. The drain field (aka “leach field”), typically is spread out almost like fingers of pipes that lead to these plastic chambers, which allow lateral movement of the liquid underground.


Very similar to the standard tank, pressure distribution uses a pump to send the liquid to the drain field. Typically, the drain field uses several lateral perforated pipes, where the waste liquid is spread out evenly. These types of systems are for more shallow depths into the ground.


These systems use a major sand filtration system to breakdown waste even more. First, waste enters the main tank, after the waste is naturally processed, it then flows through the sand filter. The sand filter is a large box consisting of a 9-inch gravel layer and then a 24-inch sand layer. The sand is a great place for good bacteria to live and breakdown waste. By the time the waste leaves the filter, it’s broken down by about 90%. From here, the waste goes through the pump tank, where it is distributed for final disposal. These are for smaller properties, with less area to put a large drain field.


This type of system is for properties with very little soil for the final distribution of waste, or properties with awkward topography. This system comprised of small “drip tubes” where constant flow and pressure pushes waste through these looped tubes. The constant pressure causes waste to breakdown and allows dispersion of final waste into a very small area. A very expensive system, and only should only be used if necessary. 


These are above ground systems on properties with little soil for the final disposal of the waste. Since these are above-ground mounds, the treatment is pressurized by gravity and pushed through sand (see sand filter). This allows for a small drain field due to the property limitations.


Similar to the sand mound. These tanks use a pump to force waste upward and out the sides, where it then flows through the sand mound to be broken down. Both sand mound and Glendon are unpopular, due to their poor aesthetic qualities.


The Main Components of Septic Tank and Leach Field Design

  • Inlet pipe
  • Septic tank
  • Outlet pipe (effluent pipe)
  • Distribution box (optional)
  • Leach Field (aka drain field)

Contact Us Today!

As you can see, we have a lot of knowledge about septic tank design and are here to help you build your dream home! As long as the county doesn’t cause you problems (which we will find out for you!), we can make sure your property is primed and ready.

Give us a call at (253) 785-9949 or fill out the contact form to request a free quote today!


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