Drain Field Replacement: How It Actually Works

Replacing a drain field is a permitted, inspected construction project — not just digging new trenches. Here's the process an Orlando homeowner goes through, step by step, and how long each stage takes.

Who regulates it

Florida's onsite sewage rules live in Chapter 62-6 of the Florida Administrative Code, administered by the Department of Environmental Protection since the Clean Waterways Act moved the program over from the Department of Health in July 2021. In Central Florida the permit itself still comes from your county health department's environmental health office — DOH-Orange for Orlando, DOH-Seminole for Sanford and Altamonte Springs, DOH-Osceola for Kissimmee — operating under DEP's rules. (DEP took over field permitting directly in sixteen Panhandle counties plus Marion in January 2025; that change does not affect the Orlando metro.) The work must be performed by a business holding an active Septic Business Authorization with a registered septic tank contractor behind it.

The replacement process

1. Site and soil evaluation. A qualified evaluator digs a soil profile to at least 48 inches, identifies the soil series and any restrictive layers, and estimates the seasonal high water table. This single document decides whether you get a conventional field or a mound: Florida requires 24 inches of unsaturated soil below the trench bottom. Setbacks are checked at the same time — 75 feet from drinking wells, 50 feet from surface water, which matters on Orlando's lakefront lots.
2. Repair/replacement permit application. Your contractor files the site evaluation, a system design sized to your bedroom count, and a site plan with the county health department. Straightforward replacements are often approved in days; engineered mound systems, and anything near Wekiwa Springs or inside a Basin Management Action Plan nutrient watershed, take longer and may require an enhanced nutrient-reducing design.
3. Utility locates and excavation. After 811 locates, the old field is abandoned or removed. In Orlando's sandy soil the digging itself is fast — trenching a typical field takes a day or two — but saturated ground in the wet season can stall this stage, which is why contractors prefer dry-season installs.
4. New field construction. Trenches or a bed are laid with gravel and perforated pipe, or with gravelless plastic chambers (approved statewide and common here because they handle Central Florida's summer surge flows well). A new distribution box splits flow evenly across the lines. Mound systems add engineered sand fill and a pump chamber that doses effluent up into the mound on a timer.
5. County inspection — before backfill. The health department inspects the open excavation to verify depths, separation from the water table, materials, and setbacks match the permit. Nothing gets covered until this passes.
6. Backfill, grading, and final approval. The field is covered, graded to shed rainwater (important with 50 inches of rain a year), and seeded or sodded. Keep the final approval paperwork — buyers and their lenders ask for it.

Realistic timeline

Emergency situations (sewage in the house) can often be bridged with frequent tank pumping while the permit processes.

Living through it

During the construction days you'll be asked to minimize water use — short showers, hold the laundry — because the tank has nowhere to send effluent until the new field is connected. The yard over the new field will look rough for a season; don't drive on it, don't plant trees within about 10 feet of it, and let only grass grow over it. An effluent filter on the tank outlet (a $50–$150 part) is the cheapest thing you can do to make the new field last its full 20–25 years.

Cost detail for every stage is in the cost guide. Not sure you need full replacement? Read repair vs replacement first.