If you own land in SC or are considering purchasing a lot that has been denied a conventional septic permit by DHEC, what should you do?
Some of the answer depends on how valuable the land is and how determined you are to build on that particular piece of property.
First off, why did DHEC deny you for a conventional septic?
Is it because you don't have anywhere on the property that allows for the required setback from a well, a stream, a property line, lake etc?
If you can't get past the necessary setback requirements, your project may not have anyway to move forward. SC rules do not allow for setback reductions or automatic drain field size reductions as a result of using onsite wastewater treatment technology. Other states, such as North Carolina, do allow for these reductions.
If the issue killing the permitting process is the soil type on the property, then that is a hurdle that a good soil assessor and engineer can possibly clear.
When DHEC runs into restrictive soil types with a low long-term acceptance rate (LTAR) they do not have the tools necessary to design a system that will confidently last a lifetime. LTAR describes how many gallons per day per square foot (gpd/sqft) of soil can be applied daily and the system not fail.
Landowner wants to build a 3 bedroom home on Lake Murray. Onsite rules dictate that a septic system for a 3 bedroom home be designed to handle 360 gallons per day of water usage at residential strength. DHEC denies the lot for a conventional system due to soil limitations.
A soil assessor assesses an LTAR of .2 gpd/sqft to a specific section of the property that meets all set back and buffer requirements. .2gpd/sqft requires a very precise dosing of the wastewater and ideally the wastewater will have been treated before dosing to insure the soil does not fail.
360gpd divided by .2gpd/sqft = 1800 sqft of required area
A .2 gpd/sq ft LTAR will require 1800 sq ft of disposal or drain field area with a 50% repair area of 900 sq ft.
By using treatment and drip dispersal in their design an engineer treats the wastewater removing many of the nutrients which reduces how hard the soil has to work to receive the wastewater. The drip dispersal irrigation doses the drain field very precisely making more of the land usable when the soil has a low, precise LTAR.
When you use a drip irrigation dispersal method in conjunction with Advantex treatment, you are able to install the drain field shallowly, on slopes, in trees and on different areas of the property.
A shallow water table can also be an issue that kills a conventional septic system, treated effluent dispersed with drip irrigation can be installed very shallowly to create the required distance to the water table or soil wetness condition.
Get in touch, I will be happy to discuss any onsite wastewater, septic, engineered septic questions you may have.