PID Cost Methodology
There are three ways Niwot’s roads get paid for, and only three. This document prices all of them the same way, from the same parcel data, so they can be set side by side. Written for a reader who wants to check the arithmetic rather than take it on trust.
Purpose and Scope
Niwot’s roads are going to be paid for by the people who drive on them. That is not a campaign position; it is the only arrangement on offer. Boulder County stopped repaving subdivision streets in 1995, and the two incentives that once made a Public Improvement District affordable — a 30% county contribution toward the initial project and interest-free county financing — are no longer offered.
What remains is a choice among three structures:
- A neighborhood PID, in which one subdivision forms its own district and pays for its own streets.
- A townwide PID, in which the whole community forms one district and pays for all of them.
- Incorporation, in which a town funds the same road program out of a broader tax base that includes sales tax.
This document derives the cost of each, per household, at the same home. It does not argue for one. It shows the arithmetic and marks clearly where a judgment was made and in which direction.
Every figure here is reproduced by a script that reads the source data directly. Where this page and the script disagree, the script is right and this page is stale. Anyone reviewing the analysis is welcome to the working.
What Is Observed and What Is Chosen
A mill levy is a ratio: the dollars a district must raise each year, divided by the assessed value it can levy on. Four things determine it. Two are observed, one is set by engineering estimate, and one is an open question of district design.
| Input | Value | Basis |
|---|---|---|
| Assessed value of the base | $183.5M–$207.9M | Observed. Boulder County Assessor, parcel by parcel, 1,837 parcels |
| Road area to rebuild | 3.81 million sq ft | Observed. Measured street by street, with pavement condition scored by County engineering in 2024 |
| Construction cost | $11.00/sq ft | County estimate. Boulder County’s own 2025 PID reconstruction cost, escalated 3% a year |
| Financing | 20 years at 4.62% | Quoted. Piper Sandler amortization, the same terms used in the town budget model |
| Who is in the district | — | Undecided. Worth about two mills. Discussed below |
The property side is checkable by any resident against their own assessment notice. The construction side rests on the County’s own cost figures, which matters: the County sets the level it will agree to fund, so the County’s number is the one that governs, not a contractor’s estimate.
The Source, and What Had to Be Corrected in It
The underlying work is a committee spreadsheet that prices all 23 Niwot neighborhoods individually against 2,015 County parcel records. Rebuilding it line by line turned up six errors, all of which are corrected here. Four are arithmetic. Two are a different and more consequential kind: the tax base was summed over the wrong parcels, so a neighborhood was charged for one set of streets while a different set of households was billed.
| What was wrong | Effect |
|---|---|
| One neighborhood’s tax base was summed from the four neighborhoods above it in the table rather than its own | Reported 19.34 mills where the same model gives 41.52 |
| Another neighborhood’s parcel range pulled in properties from elsewhere, producing an implied average home of $3.6M | Reported 19.33 against 32.02 |
| One neighborhood amortized its construction cost before inflation while every other amortized it after | Understated by 2.3 mills |
| One neighborhood carried a rounded placeholder of 30.00 where the computation gives 38.50 | Understated by 8.5 mills |
| One neighborhood’s base was summed over a street of the same first name but a different suffix — Meadow Lane rather than Meadow Lake Road — while Meadow Lake Road is 54% of the pavement being rebuilt | Overstated by 7.5 mills |
| One neighborhood’s base was summed over a block of parcels belonging to an adjoining subdivision entirely | Understated by 1.0 mill |
Four of the six understated the cost of a PID, which is to say they ran in the campaign’s favor. We corrected them anyway. A figure that only survives because nobody checked it is not worth publishing.
The fifth is worth dwelling on, because it is the one that would have done real harm. A neighborhood was being charged for a road whose residents were not in the district paying for it — fifteen households on a street that is more than half the pavement, absent from the tax base, while twenty-three households carried the entire bill. That produced a levy of 38.90 mills where the corrected figure is 31.41, and a letter quoting the wrong one would have told those households they faced roughly $780 a year more than they do. The corrected figure independently reproduces what an entirely separate model built ten weeks earlier gives for the same neighborhood, which is the strongest confirmation available that it is right.
One consequence is worth stating plainly. The same spreadsheet contains an earlier and a later version of the whole calculation, and on one neighborhood they appeared to disagree by a factor of 2.3 — which for a time looked like grounds to distrust the entire source. It was the first error in the table above: a single cell. Corrected, the two versions agree within 2.4 mills on that neighborhood, and within 3.8 mills on average across the nineteen that appear in both.
Neighborhood PIDs
For each neighborhood the calculation is the same. Measure the street area. Multiply by the County’s reconstruction cost. Escalate to the year the work would be done. Amortize over twenty years. Add the annual maintenance the roads will need afterward. Divide by that neighborhood’s own assessed value.
Streets already in good condition are treated differently from streets that are failing. A street projected to stay above a pavement condition index of 70 does not need full-depth reconstruction yet, so it is left out of the capital project — but it still enters the maintenance program, because every road eventually needs work. Four neighborhoods therefore rebuild less street than they maintain. Old Town Niwot is the clearest case: it has the best pavement in town and rebuilds roughly a third of its street area, which is why it sits near the bottom of the range.
Across the 23 neighborhoods the result runs from 18.23 mills at the low end to 45.28 mills at the high end. The published figure is 18 to 45 mills.
| Neighborhood PID | Mill levy | Median home, per year | Per month |
|---|---|---|---|
| Lowest — Johnson Valley | 18.23 | $1,265 | $105 |
| Typical, as published | 32.00 | $2,220 | $185 |
| Average across all 23 | 33.98 | $2,357 | $196 |
| Highest — Meadowdale | 45.28 | $3,141 | $262 |
What separates one neighborhood from another is mostly street area per household. A subdivision with wide streets, long cul-de-sacs and few homes has more pavement to pay for and fewer people to pay for it. That is why neighbors comparing notes will find very different numbers, and why the spread is not a sign of error.
The low end matters more than its size suggests. Until September 2026 this range was published as 20 to 40+ mills. The real floor is 18.23, and quoting 20 made the cheapest possible PID look more expensive than it is — rounding in the direction that favored our own argument. It has been corrected.
The Townwide PID: Measuring the Base
A townwide district spreads the same road program across every property in Niwot. The annual requirement is $3,051,636 — twenty-year debt service on $25.8M of reconstruction, plus ongoing maintenance.
The question is what to divide it by. Rather than adopt a tax base figure from the spreadsheet, we measured one from the parcel records. The spreadsheet’s own townwide base is exactly $2,825,000 divided by 0.015 — back-solved from an assumed 15-mill target rather than counted. Dividing a fresh cost estimate by a base that an older mill target defined is circular, so we did not use it.
Counting instead, using the County’s own assessed values and excluding tax-exempt property, gives two boundaries that differ by one real question:
| Tax base | Parcels | Assessed value |
|---|---|---|
| The 2025 PID boundary — downtown excluded | 1,808 | $183,487,666 |
| The whole town — downtown included | 1,837 | $194,799,896 |
| Business Personal Property, Niwot Tech Center | — | $13,100,000 |
The 2025 proposal left the downtown business district out of its district — 23 parcels on Second Avenue and five in Cottonwood Square — because downtown already pays into the Local Improvement District. That is a defensible design choice, and it is also a real transfer: every dollar of assessed value outside the district is a dollar the rest of the community makes up.
Business Personal Property is the second question, and the spreadsheet never addressed it. Equipment at the Tech Center is taxable property assessed at 25%, and a townwide district would ordinarily levy on it. Leaving it out raises everyone else’s rate by about a mill.
Cross-check. The town budget model projects $833,000 of property tax at 4 mills, which implies a base of $208,250,000. The parcel count above, with downtown included and Business Personal Property added, comes to $207,899,896 — a difference of two tenths of one percent. Two independently assembled figures agreeing at that tolerance is the strongest evidence available that the base is right.
| Townwide PID | Real property only | Including Business Personal Property |
|---|---|---|
| Downtown excluded — the 2025 boundary | 16.63 mills | 15.52 mills |
| Downtown included — the whole town | 15.67 mills | 14.68 mills |
The range is 14.68 to 16.63 mills, and the whole of it is a question about who is in the district. Neither question has been decided, and each is worth about a mill.
Why a Mill Levy Does Not Rise With Inflation
This is the part that is most often gotten wrong, including by us in earlier drafts, and it is worth setting out carefully.
A mill levy is a ratio. Construction costs inflate, and so do property values. If both rise 3% a year, the numerator and the denominator rise together and the rate does not move. A district needing 16.63 mills in today’s dollars needs 16.63 mills in 2029 dollars. Inflation cancels.
It follows that quoting a cost in one year’s dollars against a tax base in another year’s produces a number that means nothing. It is an easy mistake to make — the source spreadsheet amortizes its construction cost before inflation in one row and after it in the next — and it always makes the levy look smaller than it is.
What does not cancel is deterioration. As pavement falls below a condition index of 50, a street that could have been resurfaced now needs full-depth reconstruction, which costs several times as much. That grows the numerator without touching the denominator. Between the 2024 and 2027 condition assessments, 2.4 miles of Niwot street fell below 50 and another 1.6 miles below 70, adding $2.74 million of scope:
| Townwide PID, downtown excluded | Mill levy |
|---|---|
| On 2024 pavement condition | 15.49 |
| On 2027 pavement condition | 16.63 |
| Three years of deferral | +7.3% |
So the levy falls over time only if property values appreciate faster than construction inflation and road deterioration combined. In Niwot they do not:
| Annual rate | |
|---|---|
| Property appreciation | 3.81% |
| Construction inflation | 3.00% |
| Deterioration — added scope | 2.39% |
| Cost side, combined | 5.39% |
Costs outrun values by roughly a point and a half a year. A PID quoted at 15 or 16 mills today is a floor, not a ceiling, and every year of deferral raises it. This is the same conclusion the road cost model reaches from the other direction: the price of waiting is not inflation, it is scope.
The Three Options, at the Same Home
All three figures below are for the same median Niwot dwelling, valued at $1,090,100, using the statutory $70,000 value reduction and the 6.8% residential assessment rate. Pricing one option at a median and another at an average is the most common way this comparison is made to mislead, and it is avoided here.
| How the roads get paid for | Per year | Per month | What it covers |
|---|---|---|---|
| Incorporation — 4 mills plus 2.5% sales tax | $716 | $60 | Roads, snow removal, land use, wage authority, a permanent vote |
| Townwide PID — 14.68–16.63 mills | $1,018–$1,154 | $85–$96 | Roads only |
| Neighborhood PID — 18.23–45.28 mills | $1,265–$3,141 | $105–$262 | Your own streets only |
Three things follow from the table, and they are worth separating from any argument about them.
First, the cheapest possible PID outcome in Niwot still costs more than incorporation — and that cheapest outcome requires the whole town in one district, downtown included, business equipment in the base, and the work starting before the pavement degrades further.
Second, the reason is structural rather than rhetorical. A PID is funded by property tax alone. A town also collects sales tax, and a meaningful share of that is paid by people who do not live in Niwot — visitors, contractors, and deliveries into the boundary. The same road program spread across a broader base costs any one household less. That is the whole of the difference.
Third, a PID cannot legally plow snow. A Public Improvement District funds capital improvements. Snow removal is an operating service, and it stays with the County under every PID scenario.
Where We Rounded, and Which Way
A comparison that favors one side is worth nothing, so the rounding rule here is to round against ourselves. Where a judgment could go either way, we took the one that makes a PID look cheaper and incorporation look less advantageous.
| Figure | Derived | Published | Direction |
|---|---|---|---|
| Neighborhood PID floor | 18.23 | 18 | Rounded down — against us |
| Neighborhood PID ceiling | 45.28 | 45 | Rounded down — against us |
| Neighborhood PID typical | 33.98 | 32 | Understated by 2.0 mills — against us |
| Townwide PID | 14.68–16.63 | 14–16 | Understated at both ends — against us |
The published typical neighborhood figure of 32 mills predates this analysis and is about two mills below what the parcel data produces. We have left it where it is rather than raise it. A number that overstates what a neighbor would pay is the one kind of error this comparison cannot afford, even when correcting it would help the argument.
One caveat in the other direction, stated so a critic does not have to find it. The typical neighborhood figure of $185 a month prices the town median home at an average neighborhood rate. A household actually pays its own neighborhood’s rate on its own home, and across the 23 neighborhoods that averages closer to $268 a month. The published figure is the conservative one.
What This Does Not Settle
Three questions remain open, and none of them are rhetorical.
- Who would be in a townwide district. Whether downtown is included, and whether business equipment is in the base, together account for the entire 14.68–16.63 range. Both are decisions a district’s organizers would make, not facts to be discovered.
- What the County would agree to fund. Every figure here assumes County reconstruction standards at County cost estimates, with no contribution and no subsidized financing. If the County were to restore either incentive, every PID number falls.
- Pavement condition after 2027. The condition scores are engineering projections from a 2024 survey. If the roads degrade faster than 2 points a year, the levies rise faster than shown here. If slower, they rise more slowly. They do not fall.
We will publish revisions to this page when the answers change the figures, including when they move against us. Two corrections have already been made in public on the household cost figure, and both raised it.
Sources
- Boulder County Assessor — parcel-level actual and assessed values for all 2,015 parcels considered, with boundary and district membership flags
- Boulder County engineering — pavement condition index survey, 2024, scored street by street
- Boulder County — 2025 Public Improvement District cost schedule: $11.00/sq ft full-depth reconstruction, $5.00/sq ft mill and overlay
- Boulder County — Subdivision Paving PID program
- Piper Sandler — twenty-year amortization schedule at 4.62%
- Pro Forma Budget v1.5 — revenue note R1, assessed value base and growth assumptions
- The PID Proposal — the 2025 citizen proposal and its boundary
- Household Cost Methodology — the derivation of the $60 figure and the median home value used throughout
The calculations behind this document are kept as scripts rather than spreadsheets so they can be re-run against changed inputs, and so that an error in one of them can be found by reading it. That is how the four corrections above were found.