How To Prep For A Septic Tank Installation

Posted on: 2 December 2019

Whether you're preparing to do the job yourself or planning to hire a septic system service contractor, installation projects require a good deal of forethought. Add these three items to your checklist to make sure your septic tank installation effort goes as well as possible.

Check Groundwater Levels

Especially if you're doing a completely new install at a site, it's critical to make sure you can even put in a septic tank at your location. One of the biggest factors that dictates the likely success of a project is whether the seasonal high water table level will allow the tank and supporting elements to operate properly. Depending on the percolation rate, this may range anywhere from a minimum depth of 3 to 20 feet. Every state has its rules, and some prohibit septic tanks if percolation rates appear to be prohibitive. You can find historic groundwater table data on the USGS website, but you'll have to have percolation rates tested at your location.

Hard freezing may also be an issue in colder regions. It's a good idea to make sure your tank is buried below the frost penetration line for your area.

Distance From Outside Water Sources

It's also wise to keep some distance between your septic tanks and nearby water features like wells, streams, reservoirs, and drainage zones. In most cases, you'll need at least 50 feet of distance, and 100 feet may be necessary for some situations. You should contact your county's environmental compliance officer to learn what the regulations are where you live.

Planning for Capacity

Not surprisingly, the amount of wastewater flowing out of a location dictates how much capacity you'll require. This can range from 900 gallons of effective capacity for locations that flush less than 500 gallons per day to more than 5,800 gallons of effective capacity at sites that have more than 5,000 gallons of flow per day.

Calculating capacity requirements begins with considering that your water usage. On average for an American family, a toilet will consume about 33 gallons of water per day, a shower 28 gallons, and a faucet 26 gallons. Washing machines go through about 23 gallons per day, and dishwashers operate at a highly efficient 4 gallons. A good conservative assumption is to add 17 gallons per day for possible leaks. Depending on the cost of going bigger with a septic system, it may be worth investing in more efficient fixtures.