Twenty to thirty years is typical where the tank has been pumped on schedule. Fields die early for two reasons: solids reaching the soil because the tank was neglected, and constant saturation from leaks or surface water.
What failure actually looks like
Wet ground and lush grass are late signs
By the time effluent is surfacing, the soil interface has already sealed. The earlier signs are quieter: drains that get slower each month, a tank that sits above its outlet, gurgling that started after the last pump-out, or grass over the bed that greens up first in spring and stays soft after dry weather. Those are set out in full on drain field failure signs.
The cause matters because it decides the fix. Solids carryover from an overdue tank or a broken tee seals the trench bottom, and that damage is permanent. Hydraulic overload from a leaking fixture or a downspout discharging over the bed saturates the soil without sealing it, and that one can be reversed once the water source is fixed.
So the sequence is: confirm the tank is not the cause with a pump-out and inspection, check the distribution box is sharing flow evenly, then probe the bed. Replacement is what you do when those come back clean and the trenches still will not take water.
Confirmed before quoting
Cause
Where trenches still work
Partial repair
Filed for you
Permit
