How Bilby works
Private well costs
A well allowance, not a drilling prediction
Bilby can show a configured regional well range when the property appears outside the municipal water service area. That project-specific result is retained before the national budget reference of 80,000/130,000/250,000 SEK. Nearby wells provide useful evidence about local conditions, but their depth does not directly multiply a drilling rate in this estimator.
Ordinary household well
The national reference covers an ordinary drilled well, casing, pump and a basic commissioning/water-test allowance. It excludes a long on-plot trench, treatment of unsuitable water, wastewater installation and municipal water fees. In a private VA package the well is a component of the parent, not an additional charge. A mixed project may need a well for water while using municipal sewer; select that service arrangement rather than adding two full packages.
Evidence and price inputs are different
Evidence changes review warnings and confidence. Only the selected configuration or replacement quote sets this well amount.
| Input | Unit | Use |
|---|---|---|
| Municipal water service-area status | status | Whether private water is likely |
| Region and estimate year | region / year | Configured typical range |
| Nearby well depth/capacity/count | m / litres/hour / count | Evidence and warnings |
| Actual contractor price | SEK | User-supplied replacement |
Regional range before fallback
The regional function copies the configured low and high well amounts when water is outside the service area; it does not estimate metres drilled. An absent region leaves that analysis amount unavailable. The project budget can then use the national fixed reference, while preserving missing-data warnings. A range with only endpoints can be shown with a midpoint expected amount by budget conversion. A nearby-well median of at least 100 m or maximum of at least 150 m raises a deep-well warning; it does not reprice the regional range. Unknown water quality is also flagged.
Illustrative configured well
Suppose a fictional regional configuration says 90,000–150,000 SEK and only private water is needed. The function returns that range; a midpoint display is 120,000 SEK. A nearby well at 160 m can add a warning while the amount remains 90,000–150,000. Without that regional amount, the national budget fallback is instead 80,000/130,000/250,000. These two ranges are alternative evidence paths, not additive.
What missing evidence means
No nearby observations does not mean no water, and a productive neighbouring well does not guarantee yield on the plot. Low/high are planning scenarios, not confidence bounds on final drilling cost. Water treatment, access and drilling depth require a well contractor’s assessment. A real quote should identify pump, casing, testing and trench inclusions before overriding the budget.
Geology versus contractor prices
Method reviewed 18 October 2026; national price research 16 September 2026. SGU’s well information supports well evidence and guidance, not Bilby’s drilling prices. Gobis water-well scope is a contractor scope anchor. Regional configuration dates and price scope should be read on the project result.
The review date covers this explanation and its implemented method. Price and data dates are stated separately in the article.