A soakaway depends on ground infiltration, groundwater, storage and the space available. Crate count cannot be established reliably from driveway area alone. Use the dedicated calculator to explore a guide budget for the work described below.
Estimate driveway soakaways from the measurements and work options below. Guide allowances are already included; a contractor’s quote is not required to use the tool.
This is a basic per-system budget allowance. It does not size or approve a soakaway; poor ground or engineered attenuation can cost substantially more.
Guide model reviewed 7 November 2026. VAT treatment varies between published guides and supplier quotes; no VAT is added automatically. Add it only where your allowances exclude it.
The calculation separates the measured run, a basic system allowance where selected, and any connection work you enter. Infiltration testing, storage design, abnormal ground, permissions and engineered attenuation may require additional work beyond the guide.
View the published guide used for the main allowance. Optional allowances are budgeting estimates and can differ from a site-specific quotation.
Use a measured specification to compare prices for your property. Ask contractors to confirm the work, preparation, materials, access, disposal and any exclusions before agreeing a price.
Driveway Soakaways planned around your property
A soakaway depends on ground infiltration, groundwater, storage and the space available. Crate count cannot be established reliably from driveway area alone.
This is a basic per-system budget allowance. It does not size or approve a soakaway; poor ground or engineered attenuation can cost substantially more.
A soakaway depends on ground infiltration, groundwater, storage and the space available. Crate count cannot be established reliably from driveway area alone.
This is a basic per-system budget allowance. It does not size or approve a soakaway; poor ground or engineered attenuation can cost substantially more.
Enter the number of separately specified systems and any additional connecting trench length. The tool applies a basic system allowance and a separate trench-rate guide. It does not convert roof or driveway area into a storage design.
The calculation separates the measured run, a basic system allowance where selected, and any connection work you enter. Infiltration testing, storage design, abnormal ground, permissions and engineered attenuation may require additional work beyond the guide.
The first guide option is basic soakaway construction guide. Its allowance is £377–£793 for the relevant unit shown in the result. This is a published-guide starting point; it is not a price offered by a contractor on this website.
This page models basic soakaway construction guide. A different construction or repair method needs a separate allowance rather than an assumption that every job has the same scope.
The project controls include:
The results show the measured quantity, the selected work allowance and any separately selected items. A volume, unit count or coverage result is a quantity check, not a construction design. Where the model uses a minimum visit allowance or whole bags, the displayed total will not fall in direct proportion to a very small area.
Use the optional contingency to make a separate budget provision. Add a quoted fixed allowance only for work outside the model’s stated scope. Check the VAT basis before selecting the VAT adjustment.
Give contractors the same measurements and work description. Ask them to identify the main work, preparation, disposal, access requirements, drainage and any making-good that applies to this project. An apparent saving can simply mean that a different part of the scope has been priced.
This is a basic per-system budget allowance. It does not size or approve a soakaway; poor ground or engineered attenuation can cost substantially more. Keep the agreed specification with the quote, including any exclusions and the way changes discovered during the work will be authorised.
Examples use the specification named on each card, the calculator’s example measurements and guide allowances. Optional extras, contingency and VAT adjustment are off. Supply-only models exclude installation.
The calculation separates the measured run, a basic system allowance where selected, and any connection work you enter. Infiltration testing, storage design, abnormal ground, permissions and engineered attenuation may require additional work beyond the guide.
Enter the number of separately specified systems and any additional connecting trench length. The tool applies a basic system allowance and a separate trench-rate guide. It does not convert roof or driveway area into a storage design.
A soakaway depends on ground infiltration, groundwater, storage and the space available. Crate count cannot be established reliably from driveway area alone. This is a basic per-system budget allowance. It does not size or approve a soakaway; poor ground or engineered attenuation can cost substantially more.
The figures are early budgeting allowances for the work described in the selected option. This is a basic per-system budget allowance. It does not size or approve a soakaway; poor ground or engineered attenuation can cost substantially more. Ask a contractor to confirm the measured scope, access, preparation, materials and exclusions after assessing the property. The written quotation, rather than the calculator, establishes the work and the agreed price.
The result separates the main work from selected options and any additional allowance you enter. Do not add an item again if the main rate or contractor’s quote already includes it. Contingency is optional and is shown separately.
No extra VAT is added automatically. Published cost guides and supplier prices can use different VAT bases, so check the source and any written quotation. The optional VAT control adds 20% to the calculated allowances only when you select it. Leave it off when the rates or quotation already include VAT to avoid counting tax twice.
