← Irrigation Winterization Bid Calculator
This calculator vs. a flat per-zone rate
"$19 a zone" is not a price for a stop — it is a price for one specific mix of head types and backflows, quietly applied to the next house whether or not its backflow count looks anything like the first one's.
What a flat per-zone rate is
A flat per-zone rate is the fastest way to quote over the phone: multiply zone count by a number and read off a price. Homeowners like it because it is easy to compare between bids, and it is the number a prospect holding a competitor's flyer will ask you to match.
The rate was set on one stop — one particular head mix and backflow count — and then reused for the next house's zone count, whether or not that house's backflows look anything like the ones the rate was built on.
What this calculator is
This page keeps no account and sends nothing to a server. You enter each system's spray, rotor, and drip zone counts, the backflows to drain and insulate, your drive, a freeze-warning premium, and your loaded wage, compressor and fittings cost, overhead, and target margin. It turns the actual hours into a price, and reports the price per zone, the effective hourly rate, and the walk-away price below which the stop loses money — for this stop's actual backflow count, not a generic one.
| What a flat per-zone rate does | What this calculator does instead |
|---|---|
| Charges the same $/zone whether a four-zone stop has no backflow or two backflow preventers to drain and insulate — a second job the zone count never shows. | Prices the backflow drain-and-insulate time on top of the zone hours, so a backflow-heavy stop's extra labor shows up in the price instead of being averaged away into one per-zone number. |
| Assumes the stop the rate was set on is the stop being quoted, with no way to tell when the backflow count has changed. | On two otherwise identical four-zone spray stops, prices the no-backflow stop at about $76.31 and reports the two-backflow stop's target-margin price at about $96.94 — a difference the zone count alone never showed. |
| Carries a rate set on a no-backflow stop over to a two-backflow stop at the same zone count: $19.08/zone × 4 zones = $76.31. | Reports the two-backflow stop's own walk-away cost ($77.55) and target-margin price ($96.94) — the carried-over flat quote lands about $1.24 under walk-away and $20.63 short of the target margin. |
| Bakes payroll burden into a round rate nobody re-derives, so the rate quietly drifts from the crew's real loaded cost. | Loads the entered hourly wage by the entered payroll-burden percentage every time, so labor cost tracks the actual burden rather than a memorized rate. |
| Gives a number to quote, not a number to check a quote against. | Reports the walk-away price and the effective hourly rate, so a shopped price can be scored against real cost before the truck rolls. |
A flat per-zone rate is not wrong because it is simple — it is wrong when a stop's backflow count has moved away from the one the rate was set on, and nothing about a per-zone number tells you when that has happened. This calculator does not replace judgment about your market; it replaces the arithmetic a flat rate skips.
Common questions
Why does a flat per-zone rate get winterization bids wrong?
Because labor hours come from more than the zone count. A backflow preventer is its own drain-and-insulate step, not something the zone price already covers, so two stops with the same zone count can need very different time depending on how many backflows there are to winterize. A flat per-zone rate charges every stop the same for a given zone count and is wrong whenever the backflow count differs.
Can two four-zone houses really cost differently to winterize?
Yes. Take two otherwise identical four-zone spray stops with the same wage, burden, drive, compressor cost, overhead, and target margin -- one with no backflow to drain and one with two. This calculator prices the no-backflow stop at about $76.31 and reports the two-backflow stop's walk-away cost at about $77.55 and its target-margin price at about $96.94: the backflow count alone moves the job from a $76 stop to a $97 one.
What happens if a rate set on one stop is quoted on another?
On the pair above, the $19.08-per-zone rate that holds the target margin on the no-backflow stop comes to $76.31 if quoted on the two-backflow stop's identical four zones -- about $1.24 under that stop's own walk-away cost of $77.55, and about $20.63 short of the price that would actually hold the target margin there. The flat rate does not know how many backflows the stop has.
Is a flat per-zone rate ever the right way to quote?
For a narrow band of similar stops -- close to the same head mix, backflow count, and drive -- a flat per-zone rate can land close. The risk is carrying a rate set on one stop's backflow count over to a stop with a different one, because the zone count looks the same either way and nothing about the rate itself says the backflow count has changed.
Does this calculator know what to charge in my market?
No. It has no data on local rates or what competitors charge. It takes the zones, backflows, drive, and freeze-warning premium you enter for each stop, plus your wage, burden, compressor and fittings cost, overhead, and target margin, and turns that into a price, a price per zone, and the walk-away price below which the stop loses money -- the arithmetic a flat per-zone rate skips, not a market survey.
Nothing here says or implies that quoting a flat per-zone rate is a bad-faith practice — it is a common, honest shortcut that works until a stop's backflow count stops matching the one the rate was set on. This page describes where that shortcut breaks down, not a fault in anyone who uses it. The $76.31, $77.55, $96.94, $1.24, and $20.63 figures above are this calculator's own arithmetic on the two example stops described in this page, not a claim about any specific contractor's real costs.
Open the Irrigation Winterization Bid Calculator to price your own stop, or see how much should I charge for a sprinkler blowout and this calculator vs. Jobber.