Construction work in Washington County, Mississippi requires a permit, and the county Planning, Zoning & Engineering Department is the starting point for land-use and building questions12. That office also handles zoning issues, floodplain administration and access permits3. A new onsite wastewater system requires a Mississippi State Department of Health Permit/Recommendation4.
At a glance
- Building permit
- Required for construction work; start with county Planning12
- Zoning
- County records document zoning districts, but the complete current map and district schedule were not confirmed5
- Septic permit
- Required through the Mississippi State Department of Health for a new onsite system46
- Owner-builder
- A licensing exemption may cover work on your own residence, but it does not waive permits or other approvals7
- RV or tiny home
- Private-land occupancy rules are not confirmed; ask county Planning about the parcel2
- Septic soils
- Only 0.1% of county soils lack severe limits for a conventional drain field8
- Wastewater
- Gray water and other wastewater must go to sewer or septic, not onto the ground9
Who to call
Planning & zoning
Washington County Planning, Zoning & Engineering Department
Land use, development review, building policies, zoning issues, floodplain administration, engineering standards, and right-of-way, special transport and access permits
Septic permits
Mississippi State Department of Health, Division of On-Site Wastewater
Onsite wastewater applications, soil and site evaluations, permit recommendations, inspections and complaints
Contact details are copied from each office’s official page and were checked against it on September 29, 2026.
Do you need a building permit in Washington County, Mississippi?
Construction work in Washington County requires a permit1. Start with the Washington County Planning, Zoning & Engineering Department before ordering plans or beginning work because the county page assigns that office development review and building-policy responsibilities2. We could not confirm the county's permit triggers, application form, inspection sequence, certificate-of-occupancy rule or building-permit fees; ask Planning which requirements apply to the specific parcel and project3. Mississippi's owner-builder exemption can cover a person constructing or improving the person's own residence or acting as general contractor, but it is a licensing exemption and does not waive building permits, inspections, zoning, septic or utility requirements7. Agricultural buildings and buildings used for agricultural purposes likewise have a residential-builder licensing exemption, not a blanket exemption from county approvals10.
Who handles building and zoning questions in Washington County?
Start with the Washington County Planning, Zoning & Engineering Department for county building and land-use questions2. The department assists with land use, development review, building policies and zoning issues, oversees floodplain administration, and coordinates right-of-way, utility and access permits3. The county's published material does not provide a complete application workflow, so ask the office to identify the required building, zoning, floodplain and county-access reviews for the parcel3. For land inside an incorporated municipality, ask the city as well because Mississippi permit requirements vary by local government11. County Planning can be reached at 662.334.2647 or [email protected]2.
Does Washington County have zoning?
Washington County records document zoning districts, including A-1, C-3 and RE1, while the Planning, Zoning & Engineering Department handles zoning issues and land-use review52. We could not confirm a complete current zoning map or district schedule, whether county zoning covers every unincorporated parcel, or the applicable minimum lot size, setbacks, lot coverage, building height or minimum dwelling size. Ask county Planning to identify the parcel's jurisdiction, district and dimensional rules before treating rural land as unrestricted2. The office also oversees floodplain administration, but its page does not publish the operative ordinance, permit thresholds or numerical standards12. Properties inside a municipality may have different local requirements because Mississippi permit requirements vary by local government11.
How do septic permits work in Washington County?
The Mississippi State Department of Health administers onsite wastewater permitting in Washington County, and a new system requires its Permit/Recommendation64. Submit the application, property documents, plot plan and fee; MSDH performs the soil and site evaluation13. The Notice of Intent plus Final Approval fee is currently $197.50, with a processing fee for online payment and possible future changes14. If a sewer line is within 1 mile, MSDH refers the application toward sewer service and requires the provider's rejection letter before proceeding13. A qualifying first residence on at least 2 acres, or second residence on at least 5 acres, may use the limited exemption process, but the owner must still apply and install the permitted system15. Only 0.1% of county soils lack severe limits for a conventional drain field, so arrange the site evaluation before relying on a standard system8.
Can you live in an RV or tiny home in Washington County?
We could not confirm a Washington County rule allowing or prohibiting full-time RV living, temporary camping or tiny-home occupancy on private land. Ask the Planning, Zoning & Engineering Department for the parcel's zoning district and occupancy rules before buying or moving a unit onsite2. Septic rules still apply to alternative living arrangements: MSDH treats a house, trailer, manufactured home or similar single-family residence as a residential application, while multiple trailers, cabins or RVs can require a commercial-development application16. A permanent water-meter connection requires a permanent sewage-disposal solution through sewer or septic17. Mississippi requires all wastewater, including gray water, to be piped to a central sewer or septic system and prohibits discharge onto the ground, into ditches or into bodies of water9.
Building a home in Washington County: steps in order
- Ask Washington County Planning to identify the parcel's jurisdiction, zoning district, building-permit process, floodplain review and access requirements13.
- Determine whether public sewer is available; a permanent sewage solution is required before a permanent water meter can be connected17.
- If septic is needed, submit the MSDH application, property documents, plot plan and fee before finalizing the house location13.
- Install the system shown in the MSDH Permit/Recommendation; gray water and other wastewater cannot be discharged onto the ground49.
- Ask county Planning whether county-road access approval applies, and obtain an MDOT permit for a driveway connecting to a state highway1819.
- If acting as your own general contractor, confirm that the owner-builder licensing exemption fits the project without treating it as a waiver of permits or inspections7.
What should you check before buying land in Washington County?
Confirm the parcel's jurisdiction, zoning district, floodplain status and legal road access with Washington County Planning before closing51218. Order the MSDH site evaluation early because only 0.1% of Washington County soils lack severe limits for a conventional drain field8. Mississippi does not require a septic inspection solely because real estate changes hands, but MSDH recommends one; advanced treatment systems require an installer or certified manufacturer's representative to inspect the tank as part of that inspection20. The county is very flat, with 98.7% of land at a slope of 15% or less, so parcel-level drainage and flood review deserve attention even when construction access looks easy21. If the land will be divided, MSDH generally treats development into 10 or more lots as a subdivision for wastewater review, while county rules may set a lower threshold22.
Watch-outs
- Construction work in Washington County requires a permit, but the county's published page does not state the triggers, inspection sequence or certificate-of-occupancy rules; ask county Planning before work begins13.
- A sewer line within 1 mile can redirect an MSDH septic application to the sewer provider unless that provider issues a rejection letter16.
- Only 0.1% of Washington County soils lack severe limits for a conventional drain field, so do not assume a standard septic layout will work8.
Sources
- Residential Application and Licensing Information, quoted and re-checked
- Washington County Planning, Zoning & Engineering Department (washingtoncounty.ms)
- Planning, Zoning & Engineering, quoted and re-checked
- On-Site Wastewater, quoted and re-checked
- Washington County Board of Supervisors Minutes, August 6, 2012, quoted and re-checked
- On-Site Wastewater Online Application FAQ, quoted and re-checked
- Residential Laws and Rules Revised 2022, quoted and re-checked
- Share of soils without severe limits for a conventional septic drain field (USDA SSURGO): Bolthole Index county data
- On-Site Wastewater Online Application FAQ — Sanitation and utility conditions, quoted and re-checked
- Residential Laws and Rules Revised 2022, quoted and re-checked
- Start Your Business in Mississippi — County and City Permits (Mississippi statewide rule), quoted and re-checked
- Planning, Zoning & Engineering, quoted and re-checked
- On-Site Wastewater, quoted and re-checked
- On-Site Wastewater Online Application FAQ — Fees and process, quoted and re-checked
- Notice of Intent: New Individual On-site Wastewater Disposal System, quoted and re-checked
- FAQs and Answers — WasteWater, quoted and re-checked
- WasteWater Frequently Asked Questions, quoted and re-checked
- Planning, Zoning & Engineering, quoted and re-checked
- Mississippi Access Management Guide (Mississippi statewide rule), quoted and re-checked
- WasteWater Frequently Asked Questions, quoted and re-checked
- Share of land at 15% slope or less: Bolthole Index county data
- Wastewater Application FAQ, quoted and re-checked
Written September 29, 2026 from the rules quoted below, each taken from an official source and re-checked by an independent reviewer. This is research, not legal advice: rules change, so confirm with the office before you buy or build.