What is a drain field?

The drain field — also called a leach field or absorption field — is the part of a septic system that disposes of the liquid leaving the tank. Perforated pipes laid in gravel trenches or a bed let the water soak into the soil, where it is filtered. The tank holds the solids; the field does the disposal.

How do I know if my drain field is failing?

Soggy ground or unusually green grass over the field in dry weather, sewage or gray water surfacing in the yard, drains slowing throughout the house after rain, or a tank that suddenly needs pumping far more often than it used to. Any of those is worth a look before it becomes a backup indoors.

Can a drain field be repaired, or does it have to be replaced?

Often it can be repaired. A crushed or blocked line, a broken distribution box or a missing outlet baffle is a component fix. A field that is clogged with solids or sitting in saturated ground usually needs new trenches in fresh soil, and where the lot has no room for that, an aerobic treatment unit is the alternative. We inspect first and tell you which one you are looking at.

Does drain field replacement need a permit in Hawaiʻi?

A new or replacement disposal system requires Hawaiʻi Department of Health approval, and the design is permitted before any digging starts. Most straightforward component repairs do not. We handle the permitting either way.

Why do drain fields fail on Oʻahu?

Two ways. They clog, from solids carried past a missing outlet baffle or from too many years between pump-outs, and they drown, when heavy rain saturates ground that was marginal to begin with. Vehicles parked over the field and roots in the lines finish plenty of them off.

How much does drain field repair cost?

It depends on how much of the field has to be rebuilt and what the soil will take, which is why we quote after seeing it rather than over the phone. The estimate is free and in writing. Call (808) 630-9966.

Drain Field Repair & Replacement in Honolulu & Oʻahu

septic system and drain field being installed on Oʻahu

buried septic tank uncovered for inspection on Oʻahu

Drain field repair and replacement on Oʻahu

The drain field is the half of a septic system nobody sees and everybody depends on. The tank separates the solids; the drain field — also called a leach field or absorption field — is the set of buried perforated lines in gravel trenches or a bed that lets the liquid soak away into the soil. When it stops absorbing, the tank has nowhere to send water, and the house finds out the wet way. Golden Penny Sanitation Inc. repairs and replaces drain fields across Oʻahu. We are a licensed and insured Hawaiʻi sanitation contractor — Hawaiʻi License CT-39138 — and we diagnose before we quote, because a field gets blamed for plenty of failures that are actually a baffle or a line.

Estimates are free. Call (808) 630-9966 and describe what you are seeing.

Drain field (leach field) repair and full replacement
Diagnosis first — tank, baffles, distribution box and lines checked before the field is condemned
New absorption trenches or beds, engineered and permitted through the Department of Health
Outlet baffle and distribution box replacement — the two parts that ruin fields when they fail
New drain fields as the disposal half of a cesspool-to-septic conversion
Free, no-obligation estimate

When a drain field needs work

A field rarely fails overnight. It clogs, from solids that slipped past a missing outlet baffle or from years without pumping, or it drowns, when Oʻahu rain saturates ground that was marginal to begin with. These are the signs, roughly in the order they show up:

Soggy ground or unusually green grass over the field, in dry weather
Sewage or gray water surfacing in the yard
Drains slowing throughout the house, especially after heavy rain
A tank that needs pumping far more often than it used to
Sewage smell outdoors near the field, before any standing water

Repair or replace is the question that matters, because the answers are thousands of dollars apart. A crushed line, a broken distribution box or a missing outlet baffle is a repair — parts, not a new field. A field that is clogged through or sits in ground that no longer drains usually needs new trenches in fresh soil. And where the lot has no fresh soil left, or the water table sits too high for trenches at all, the honest answer is an aerobic treatment unit, which treats the water in the tank and needs far less ground to dispose of it.

What the work looks like

A replacement is a permitted job, not a service call, and most of the calendar is design and approval rather than digging. Straightforward component repairs generally do not need a permit; a new or replacement disposal system does.

Pump the tank and open it — you cannot evaluate a system that is full
Locate the field and check the outlet baffle and distribution box before anything else
Evaluate the soil and the space — the percolation test decides what the ground can take
Engineered design sized to the house, filed with the Department of Health for approval
Excavate, lay the new trenches or bed, connect and test
Final inspection and sign-off, with the old field taken out of service properly

If you are replacing a cesspool rather than a failed field, the drain field is part of the new system — see cesspool conversion for the whole sequence.

What drain field work costs

Every drain field job is quoted after we have seen the ground, because the two things that set the price — how much of the field has to be rebuilt and what the soil will take — cannot be read from the curb. The estimate is free and in writing before anything begins. Call (808) 630-9966.

Drain fields and the 2050 cesspool law

Most drain fields going into Oʻahu ground today are not repairs at all — they are the disposal half of a septic system replacing a cesspool, which every Hawaiʻi cesspool has to do by January 1, 2050. The Department of Health sizes that field on 200 gallons per bedroom per day, and it is the field, not the tank, that decides whether a conventional septic system fits on your lot. Our Hawaiʻi cesspool conversion guide sets out the lot-size and bedroom rules in plain language.

septic crew working on an Oʻahu property

Diagnosis before a quote — a repairable field is not sold as a replacement
Department of Health permits filed and tracked for you
Fields sized to the house and the soil, not to the cheapest layout
One crew from the first pump-out to the final inspection
Local, licensed and insured, answering 24/7

Frequently Asked Questions

What is a drain field?
The drain field — also called a leach field or absorption field — is the part of a septic system that disposes of the liquid leaving the tank. Perforated pipes laid in gravel trenches or a bed let the water soak into the soil, where it is filtered. The tank holds the solids; the field does the disposal.
How do I know if my drain field is failing?
Soggy ground or unusually green grass over the field in dry weather, sewage or gray water surfacing in the yard, drains slowing throughout the house after rain, or a tank that suddenly needs pumping far more often than it used to. Any of those is worth a look before it becomes a backup indoors.
Can a drain field be repaired, or does it have to be replaced?
Often it can be repaired. A crushed or blocked line, a broken distribution box or a missing outlet baffle is a component fix. A field that is clogged with solids or sitting in saturated ground usually needs new trenches in fresh soil, and where the lot has no room for that, an aerobic treatment unit is the alternative. We inspect first and tell you which one you are looking at.
Does drain field replacement need a permit in Hawaiʻi?
A new or replacement disposal system requires Hawaiʻi Department of Health approval, and the design is permitted before any digging starts. Most straightforward component repairs do not. We handle the permitting either way.
Why do drain fields fail on Oʻahu?
Two ways. They clog, from solids carried past a missing outlet baffle or from too many years between pump-outs, and they drown, when heavy rain saturates ground that was marginal to begin with. Vehicles parked over the field and roots in the lines finish plenty of them off.
How much does drain field repair cost?
It depends on how much of the field has to be rebuilt and what the soil will take, which is why we quote after seeing it rather than over the phone. The estimate is free and in writing. Call (808) 630-9966.