Septic system requirements in Mississippi

What landplan.io applies when it designs a septic system in Mississippi: the system types allowed, tank sizes, setbacks and soil loading rates, with what septic products cost there.

Updated 5 October 2026

Design a septic system for an address in Mississippi

Reviewed landplan.io designs by Mississippi's own rules, which our staff reviewed against the state's regulations. Last published 5 October 2026.

6system types permitted

1,000 gallonssmallest septic tank

40septic companies located here

82 of 82counties with parcel data

Septic systems allowed in Mississippi

The system types landplan.io permits in Mississippi:

Elevated Sand Mound System
Subsurface Pressure Trench System
Subsurface Trench System
Infiltrator Advanced Treatment Leachfield
Infiltrator Advanced Enviro-Septic® (AES)
Discharging System

Septic tank size in Mississippi

The daily design flow of a home: 150 gal/day per bedroom, at least 240 gal/day. The septic tank is sized from that flow:

Septic Tank: minimum size by daily design flow
Daily design flow	Minimum tank
up to 240 gal/day	1,000 gallons
240 to 360 gal/day	1,500 gallons
360 to 600 gal/day	2,000 gallons
600 to 720 gal/day	2,500 gallons
720 to 840 gal/day	2,750 gallons
840 to 920 gal/day	3,000 gallons
920 to 1,040 gal/day	3,250 gallons

Septic setbacks in Mississippi

Minimum distances
From	To	Distance
Polygon	Existing Septic Component to be Abandoned	5 ft

These are the values the landplan.io design engine applies in Mississippi. Confirm a design with the Mississippi health department or your county's before you build.

Parcel data in Mississippi

landplan.io has parcel boundaries for 82 of Mississippi's 82 counties: the counties where 100% of the state's people live. Type an address there and the design starts from the parcel.

Septic companies, designers and jobs in Mississippi

Where the rules come from

The regulations and documents landplan.io's Mississippi rules are read from:

On-Site Wastewater Regulations (Individual Onsite Wastewater Disposal Systems) (Miss. Admin. Code Title 15, Part 18, Subpart 77)

Septic rules by county in Mississippi

Questions

What septic systems are allowed in Mississippi?

landplan.io permits these system types in Mississippi: Elevated Sand Mound System, Subsurface Pressure Trench System, Subsurface Trench System, Infiltrator Advanced Treatment Leachfield, Infiltrator Advanced Enviro-Septic® (AES) and Discharging System.

What size septic tank do I need in Mississippi?

landplan.io sizes the septic tank in Mississippi from the daily design flow: up to 240 gal/day: 1,000 gallons; 240 to 360 gal/day: 1,500 gallons; 360 to 600 gal/day: 2,000 gallons; larger flows need larger tanks. A home's design flow is 150 gal/day per bedroom, at least 240 gal/day.

Does landplan.io have parcel data in Mississippi?

Yes, for 82 of Mississippi's 82 counties.