THE ESTIMATING ANSWER
For one wet garden run, start with a defined scope and measurement basis. Record run length, trench depth, fall, soil conditions and discharge location. Separate perforated pipe, aggregate and geotextile quantities from digging and reinstatement. Price the listed tasks separately and state the condition that would require a revision: Unexpected utilities or no feasible outlet can stop the base design.
This guide uses one wet garden run as a worked, fictional job. Its matching itemized estimate and PDF let you trace the advice to actual document lines. The role considered here is general contractor. Confirm the site conditions, product selections and your own costs before preparing a client quote.
1. Define the measured job
Install a shallow subsurface drain across an accessible garden run and connect it to a confirmed lawful discharge point. Record run length, trench depth, fall, soil conditions and discharge location. Record the measurements and existing condition in the estimate before turning quantities into line items. The scope should make clear why this is a separate project from a broader renovation or maintenance quote.
Measurement basis: Record run length, trench depth, fall, soil conditions and discharge location.
2. Build a product and labor schedule
Separate perforated pipe, aggregate and geotextile quantities from digging and reinstatement. This example has 7 distinct lines, including drain route survey, service check and protection, trench excavation. Use actual supplier prices and labor inputs for a customer job; the displayed amounts are fictional document inputs.
Selections to confirm: Separate perforated pipe, aggregate and geotextile quantities from digging and reinstatement.
3. Sequence the work and handoffs
Trace buried services and confirm discharge before excavation. Show which task depends on access, a selected product or another trade. If that dependency is still open, label the price preliminary and identify the information needed before a firm quote.
Work sequence: Trace buried services and confirm discharge before excavation.
4. Set a change boundary
Unexpected utilities or no feasible outlet can stop the base design. The example excludes basement waterproofing, drainage approval or major landscape reconstruction. Record the discovery, agree the revised work and update the estimate before adding it to the job.
If the job changes: Unexpected utilities or no feasible outlet can stop the base design.
Worked project calculation
The example line for trench excavation is 90 linear ft. × $15.00 = $1,350.00. This line is one part of the complete 7-item estimate and uses a fictional unit rate.
The paired estimate has 7 separate lines. For this fictional job, multiply each quantity by its unit price and add the line amounts to get $4,660.00. The sample PDF uses these exact values, with tax and markup left at zero so the arithmetic is visible. This total is an illustration, not a regional price or an offer to perform the work.
| Cost line | Quantity | Unit price | Line amount |
|---|---|---|---|
| Drain route survey | 1 job | $210.00 | $210.00 |
| Service check and protection | 1 job | $160.00 | $160.00 |
| Trench excavation | 90 linear ft. | $15.00 | $1,350.00 |
| Perforated pipe allowance | 90 linear ft. | $8.00 | $720.00 |
| Stone and fabric allowance | 1 job | $620.00 | $620.00 |
| Pipe bedding and connection | 90 linear ft. | $12.00 | $1,080.00 |
| Backfill and turf reinstatement | 1 job | $520.00 | $520.00 |
| Illustrative subtotal | $4,660.00 | ||
Scope and pricing boundaries
Install a shallow subsurface drain across an accessible garden run and connect it to a confirmed lawful discharge point.
Outside this example: No basement waterproofing, drainage approval or major landscape reconstruction.
Separately identify supplier allowances, labor, subcontracted work and site-specific risk where they apply. Before giving a selling price, decide how your own overhead, profit and any applicable tax will be handled. Do not copy the fictional rates into a real quote without checking your own measurements and supplier or subcontractor figures.
Before you send the estimate
- Record run length, trench depth, fall, soil conditions and discharge location.
- Separate perforated pipe, aggregate and geotextile quantities from digging and reinstatement.
- Trace buried services and confirm discharge before excavation.
- Unexpected utilities or no feasible outlet can stop the base design.
Read the complete subsurface garden drain installation PDF example to see how the scope, individual prices and exclusions appear in a client-facing document. If a condition is still unknown, write that boundary into your estimate and revise the affected line once it is resolved.
Questions about this estimate
Which quantity controls this subsurface garden drain installation estimate?
Record run length, trench depth, fall, soil conditions and discharge location.
When should this subsurface garden drain installation quote be revised?
Unexpected utilities or no feasible outlet can stop the base design. No basement waterproofing, drainage approval or major landscape reconstruction.
TURN THIS EXAMPLE INTO YOUR OWN ESTIMATE
Build a subsurface garden drain installation estimate for your project
Use Estimates on iPhone or Android to draft a scope with AI assistance or enter each line yourself. Review quantities, rates, exclusions, and client details before exporting a PDF. The example is free to inspect; some app features may require an in-app purchase.
