Guide

Before you sign: five numbers to get in writing

A septic quote is a five-figure promise about work that disappears underground. These five numbers — all of which you can check — separate an installer who priced your actual job from one who quoted a template.

Crane truck setting a new concrete septic tank beside its pit at a home construction site — The moment the numbers become concrete — literally. Once the tank is over the pit, changing its size stops being a paperwork question.

1. The tank size, and the rule that sets it

Ask: "What size tank, and which state rule requires it?" A good answer names the rule — the table, the formula, or your county's code — and matches what our calculator gives for your state and bedroom count. "That's the standard size" is not an answer; there is no national standard.

2. The permit fee, from the county schedule

Permit fees are published by your county health department — typically $250–$700, more in high-regulation counties. If the quote's permit line is far above the county's own schedule, ask why. This is the easiest line on the quote to verify to the dollar.

3. The tank's price, as a line — not inside the total

Tanks have public prices: a 1,000-gallon concrete tank lists at about $1,410–$1,530 from precast yards; plastic runs $1,910–$2,400 retail. Ask for the tank as its own line, delivery separate. It keeps everyone honest and makes quotes comparable.

4. What the perc result assumed about the field

The drainfield is the biggest material cost and the part most sensitive to your soil. Ask whether the quote assumes a conventional field, and what the price becomes if the soil forces chambers, a sand filter or a mound. Get the alternate number now, not after the hole is dug.

5. The labor and excavation share

In itemized build-ups, excavation, labor and equipment come to roughly 40% of the total. If a quote's total is far above our estimator's band for your state and system, the difference usually hides here — ask what drives it: access, rock, distance, a pumped system. There may be a good answer. There should be an answer.

None of this requires being an expert. It requires the quote to be made of numbers — which is all this site asks of its own estimates, too.

Checked against the state rules cited on our state pages, Nov 10, 2026.