Custom-home site budget
The site costs a custom-home quote often leaves out
A price for the house is not necessarily a price for a ready-to-build site. Two properties that support the same floor plan can require very different excavation, utility, drainage and street work. Find the exclusions before comparing lots or signing a construction contract.
On this page8 sections
Define what the house quote actually includes
Ask the builder to draw the boundary of the quoted work. Does it start at an existing cleared pad, at the property line, or at the public main in the street? Does it include temporary power, tree protection, excavation, export, backfill, driveway restoration and final planting? A phrase such as site work included needs a written scope and assumptions.
Separate four categories: work in the base contract, allowances already included, exclusions you must buy separately, and unresolved items that are not yet priced. An allowance is part of the quoted total. Add only its expected adjustment when building the complete budget, not the allowance again.
Ask whether quoted values include tax, supervision, contractor markup and agency charges. A utility-provider estimate, a subcontractor bid and a general contractor's installed price can cover different portions of the same work. Compare the boundaries before adding the numbers.
Use a site-cost checklist before you choose a lot
| Cost family | What can be missing | Evidence that makes it priceable |
|---|---|---|
| Investigation and design | Survey, geotechnical work, arborist, drainage design, specialist reports | Written consultant scopes, field work and accepted design assumptions |
| Clearing and demolition | Hazardous materials, disconnects, tree protection, disposal, temporary controls | Demolition scope, surveys and applicable agency requirements |
| Earthwork and retaining | Excavation, export, unsuitable soil, shoring, dewatering, walls, access constraints | Civil grading plan, geotechnical recommendations and quantity assumptions |
| Water, sewer and power | Connections, service upgrades, main extensions, trenching, easements, restoration | Provider confirmation, service design and clearly separated utility and contractor quotes |
| Stormwater | Drainage study, infiltration testing, detention, treatment, conveyance and maintenance | Approved or sufficiently developed drainage concept and discharge path |
| Street and frontage | Driveway approach, sidewalk, curb, pavement, traffic control, street trees | Written city requirements and right-of-way design scope |
| Fire access and supply | Access changes, hydrants, water-supply work and sprinkler coordination | Fire-authority response and accepted supply information |
| Temporary and closeout work | Fencing, erosion controls, storage, inspections, testing, restoration, security | Construction logistics plan and permit conditions |
Bellevue civil plans for residential projects ↗ · Kirkland Fire Prevention: water supply, access and sprinkler policies ↗
A nearby utility is not a confirmed service connection
Ask each actual provider whether the proposed project can be served, from where and on what terms. City limits and utility service boundaries are not necessarily identical. Record the meter or connection point, available service information, expected upgrades, design responsibilities, fees and any outside approval.
In Bellevue, extending public water, sewer or storm infrastructure has a separate utility-extension agreement process. A line shown on a map is not evidence that an existing private service is adequate or that no extension is needed. Request the provider's answer for the proposed house and use, not just the present address.
Coordinate power, water, sewer and communications early enough to evaluate the trench route. Ask whether utilities share excavation, what must remain separate and who restores each surface. Verify off-property access and easement rights. Do not price a connection that depends on a neighbor's consent as though the consent already exists.
For [address and parcel], we are considering [project and dwelling count]. Please confirm the serving provider and connection point, what service-capacity information is available, and what design or testing is needed. Are a service upgrade, main extension, easement or outside approval potential requirements? Please separate provider charges from construction by our contractor and identify the assumptions and validity period of any estimate.
Bellevue utility extension agreements ↗ · Review easements and consent requirements →
Investigate drainage, slope and fire questions together
A slope can affect more than foundations. Excavation access, retaining walls, the driveway profile and the drainage outlet can interact. Ask the civil and geotechnical teams to review the same concept before a building shape or floor elevation becomes difficult to change.
Bellevue requires storm drainage reports for some building and utility permits and directs applicants to its current Surface Water Engineering Standards. Do not assume infiltration is feasible just because there is open lawn, or that water can be sent toward a lower neighboring lot. Obtain a site-specific drainage concept and identify the lawful discharge or management approach.
Kirkland's Fire Prevention resources address fire access, water supply and sprinklers separately. Ask the responsible fire authority which requirements apply to your proposal. Do not infer flow from the nearest visible hydrant or assume a sprinkler quote includes every service or access upgrade.
Test the construction phase as well as the finished site. If trucks cannot reach the excavation directly, how will material move? Where do protected trees, stored soil, temporary drainage and a crane or pump fit? Have bidders state the access and handling assumptions behind their prices.
Bellevue storm drainage reports ↗ · Kirkland Fire Prevention: water supply, access and sprinkler policies ↗ · Compare critical-area and site restrictions →
Make uncertain items visible in the budget
Use a register with a low and high planning allowance, the evidence available, the person who will refine it and the decision date. The range is your team's estimate, not an official regional price. Prioritize investigation where a result could change whether you buy the lot or which design you choose.
Keep contingency separate from known omitted scope. If a sewer connection is required but unpriced, list it as an unresolved connection cost. Contingency can address uncertainty around the work; it should not conceal the absence of an entire work package.
Also separate permanent expenses from financial assurances or funds temporarily tied up. Ask who calculates the required security, which form is accepted and what releases it. A deposit that may later be released can still affect the cash needed before issuance or closeout.
| Field | Example entry, not a cost estimate |
|---|---|
| Scope and status | Stormwater system / concept only / excluded from base quote |
| Price basis | Civil quantity estimate; contractor pricing not yet received |
| Possible change | Soil test or approved outlet could change the selected system |
| Owner and deadline | Civil engineer to confirm concept before builder pricing |
| Contract treatment | Allowance, fixed scope, unit rate or separate owner contract |
A worked example: avoid counting the same trench twice
Illustrative arithmetic only: an earthwork quote is $60,000 and a utility-installation quote is $40,000. Adding them gives $100,000. If both bidders confirm in writing that the same $15,000 trench excavation and restoration scope appears in both quotes, the coordinated total would be $85,000 before other adjustments.
Do not subtract $15,000 merely because both quotes contain the word trench. One might include only excavation while the other covers bedding, shoring, testing or final paving. Resolve the limits, quantities and responsibility with both bidders. The figures here are invented to show the comparison method, not typical Eastside prices.
The opposite error is a gap: each bidder assumes the other will provide traffic control or haul excess soil. Give every shared boundary an owner. Reconcile the site budget again when civil drawings, utility requirements or the construction approach change.
Put this guide to work
- Ask the builder for written inclusions, allowances and exclusions tied to the current drawing set.
- Obtain provider and city answers for utilities, drainage, frontage and fire requirements that could change the site design.
- Have the civil team and bidders reconcile quantities, construction access and overlapping scopes. Record both gaps and duplicate items.
- Keep a dated site-cost register. Resolve purchase-critical unknowns before the contract deadline and design-critical unknowns before final pricing.
Common questions
Can I budget site work as a percentage of the house price?
It can be an initial placeholder, but it is not a substitute for the actual property scope. A main extension, retaining system or difficult construction access may not scale with the house price. Replace the placeholder with investigated items.
Can I reuse the existing services when rebuilding?
Possibly, but confirm condition, capacity, location and provider requirements for the new project. An existing connection does not automatically establish the right size or eliminate current charges and upgrades.
Should I buy the cheapest lot and reserve more for construction?
Compare the lot price plus the evidence-based cost and uncertainty of making each site work. A low purchase price alone cannot establish which property is the better value for your plans.
Written and sources reviewed . This is a budgeting framework, not a contractor estimate or determination of required improvements. Local requirements and provider scopes must be confirmed for the property. Worked prices are hypothetical.