Read the calendar before you read the yard
This county is flat sand over a water table that rises sharply from June through October. Florida requires two feet of dry soil between the bottom of the field and the seasonal high water table, because that soil is what treats the effluent. When the table comes up the separation shrinks, and a field that handled everything all winter stops coping in the wet season.
So the signs fall into two groups. Spongy ground over the trenches, whole-house slow drains, gurgling and odor after heavy rain that all clear during a dry spell point to a field at capacity. The same signs persisting through a dry November point to something structural instead. Roughly 30 percent of Florida's 2.7 million septic tanks are more than 30 years old, and age shows up in the wet season first — an overdue tank has no buffer left when the table rises, which is why $300–$500 on schedule is the cheapest thing you can do for a field here.
Repairable, and not
Repairable: a distribution box that has tilted or filled and is sending the house to one trench; a lateral crushed or separated; solids carried over from a tank left too long, which seal the first few feet of stone; and hydraulic overload from a leaking fixture or a sump discharging into the system. Where the house sits below the field, a pump chamber dosing the trenches evenly rather than flooding the nearest one often buys years — adds $1,500–$3,500 where the house sits below the field.
Not repairable: a biomat sealed across the full soil face, or a field that never had the separation the code requires. In this county the usual answer to the second one is a mound or raised fill field that buys the separation back, $12,000–$25,000 (mound / raised fill / performance-based), rather than a like-for-like rebuild that will drown again next July. What replacement involves.
Check eligibility before you authorize work
Inside the lagoon protection program area a property must connect to sewer or reach at least 65 percent nitrogen reduction by July 1, 2030, and the county grant covers up to $20,000 per home toward that, with a minimum award of $6,000 for eligible parcels. Money spent patching a system you are about to replace is money the grant will not give back. Check whether your address qualifies and how the upgrade grant works.
Two local facts change the answer for some properties. New septic permits are closed in the North Indian River Lagoon under a court-ordered moratorium, so on a vacant parcel there that is the first thing to establish rather than the last. And Palm Bay has a four-year phased sewer hookup plan with outreach starting in summer 2027 — a funded connection on a known date can beat paying for an upgrade now. What the moratorium covers and the phased hookup plan.
A diagnosis visit covers the tank and sludge level, the distribution box, a probe of the trenches, and a written finding with a repair price or a replacement estimate. In Florida, altering the system requires a permit; routine maintenance does not.
All work is performed by Florida-registered septic tank contractors who are licensed and insured.