How Bilby works
Municipal water and wastewater
Which water and wastewater amount is used
Bilby first retains an available project-specific water/wastewater estimate. Depending on the analysis, that can be a configured municipal tariff, a researched local connection allowance or a selected private/mixed alternative. When no usable project amount exists, the budget can use a clearly provisional national reference. The connection fee and any private work inside the boundary must be distinguished before adding extra trenches.
Choose a service scenario
Municipal, private and mixed are alternatives, not three charges to add together. Mixed means one municipal service and the complementary private solution. A municipal package may already include ordinary private pipework and groundworks for roughly 15–30 m inside the boundary. Its allowance excludes blasting, exceptional reinstatement, pumping, network extensions and work outside the plot. Annual consumption charges are outside the one-time connection estimate. Municipal stormwater may be within the tariff; do not add the same service again as local stormwater works.
The coordinate-analysis starting choice
Coordinate analysis initially selects private VA when the stored nearby-building count within 250 m is 20 or fewer, and municipal VA above 20. A missing count is treated as zero for this starting choice. This is a planning shortcut, not service-area confirmation. You can change the scenario; the saved choice is carried into the project budget. Confirm the actual municipal services and private requirements before treating the selected estimate as settled.
Tariff inputs and evidence
A nearby connected property is evidence of proximity, not confirmation of this plot’s connection point.
| Input | Unit | Origin |
|---|---|---|
| Plot area and area cap | m² | Property data and tariff configuration |
| Applicable water / wastewater / stormwater | services | Service-area evidence |
| Dwellings and complementary dwellings | count | Project assumptions |
| Base, area and dwelling fees / service factors | SEK / factor | Reviewed local configuration |
| Special surcharge / completed private connection | SEK / status | Confirmed local/project evidence |
Configured tariff versus national reference
In the configured tariff path, chargeable area is capped. Area fee is the smaller of capped area × tariff rate and base fee + ordinary dwelling fees. Vacant-plot stage = round((base + half area fee) × service factor) + confirmed surcharge. Remaining when built = round((half area fee + dwelling fees + complementary dwelling fees) × factor). Their sum is the complete municipal fee; private groundworks are added only when configured and the private connection is not confirmed complete. Missing plot area or applicable services, or an unconfirmed special tariff area, can prevent this calculation. These stages are a particular configured method, not a universal Swedish tariff. National fallback is 100,000/185,000/400,000 SEK. Its water/sewer details allocate 45%/55% of the parent; they are not additional or published component tariffs. Mixed fallback is 150,000/300,000/600,000 SEK.
Illustrative tariff and allocation
Use a fictional configuration with 100,000 SEK base, 50 SEK/m², 40,000 per dwelling, 2,000 m² area cap, factor 1 and no surcharge. A 1,000 m² plot with one dwelling has 50,000 area fee. Vacant stage is 125,000 and remaining stage 65,000: 190,000 SEK total. A configured 50,000–100,000 private groundwork allowance makes the combined range 240,000–290,000. Separately, the national expected parent 185,000 is allocated as 83,250 water + 101,750 sewer. Adding those details to 185,000 would double the same scope.
Authority decision and package ownership
A fixed configured fee can have identical low/high while the total still varies because groundworks are uncertain. This is not a statistical confidence interval. Some public service cards divide a municipal package equally between applicable services; that is another explanatory allocation, not the 45/55 budget-reference split. Missing details may remain covered by a stored combined utilities amount. Rock, slope and pumping warnings do not automatically increase the normal package. Confirm the current local decision, service mix and included pipe route.
Local tariff and national evidence
Code reviewed 18 October 2026; the national reference collection was researched 16 September 2026. Local amounts retain their own tariff year and checked date. Svenskt Vatten’s tariff statistics provide cross-municipality context, not a quote for this plot. Bilby’s national range and 45/55 allocation are modelled planning choices; the municipality’s applicable published tariff and formal assessment control the real fee.
The review date covers this explanation and its implemented method. Price and data dates are stated separately in the article.