Soakaway Design for High Water Table Constraints
High-groundwater soakaway feasibility and design
A high water table can make a conventional soakaway unsuitable. RIDA reviews groundwater evidence, infiltration results, site levels, available area, receptors and approval requirements. See the wider soakaway design service for work outside this groundwater constraint.
Get A Free No Obligation QuotePossible feasibility outcomes
- Infiltration is potentially feasible using the available evidence.
- A revised, shallower or larger arrangement requires assessment.
- Further infiltration testing or groundwater monitoring is required.
- Infiltration is unsuitable and another discharge route is needed.
Evidence led options where depth is restricted
Restricted depth does not make a wider, shallower or multi-unit layout acceptable by default. Infiltration may need to form part of a wider sustainable drainage system design.
Request a feasibility review
Get A Free No Obligation QuoteWhat You Will Receive
| Technical deliverable | Purpose |
|---|---|
| Feasibility note covering evidence, constraints, findings and investigation needs | Supports the decision on whether an infiltration proposal should progress |
| Groundwater or infiltration investigation brief, where required | Defines the site evidence needed before design |
| Agreed-scope calculations, layout and construction detail input | Supports planning, building control and detailed drainage coordination |
| Options note or responses to reviewer comments, where commissioned | Supports an alternative drainage route or technical submission response |
Projects progressing beyond feasibility may require detailed drainage design. Deliverables are confirmed in the agreed scope and do not guarantee third-party acceptance.
What RIDA needs to assess the site
Information for a feasibility review or quote
- Site address and layout, to review the site context and available space.
- Proposed plans and impermeable areas, to define the drainage scope.
- Topographical levels, to assess usable depth and proposed flow routes.
- Ground investigation, infiltration-test results and groundwater records, to assess performance and seasonal conditions.
- Existing drainage records, nearby structures and receptors, to identify constraints.
- Planning conditions, reference numbers and authority comments, to confirm the submission need.
Groundwater, infiltration and approval considerations
One groundwater observation may not establish the seasonal high level. The assessment must reflect the site, applicable authority requirements and approval route. Relevant official references include Infiltration systems: groundwater risk assessments, the National standards for sustainable drainage systems and, for applicable England building-control work, Approved Document H: drainage and waste disposal.
If infiltration is unsuitable, RIDA can review drainage strategy options such as attenuation with controlled discharge, another receiving system or a combined SuDS treatment train, subject to permissions.
Questions before we complete your work
Can a soakaway be designed where the water table is high?
Potentially at shallow depth or by increasing the ground level. Feasibility rests on verified seasonal groundwater, infiltration performance, levels, available area, receptors and the requirements applied to the project. A conventional deep soakaway may not be suitable.
What information do you need to assess high groundwater soakaway feasibility?
Send the site address, proposed plans, impermeable areas, levels, ground investigation, infiltration results, groundwater records, existing drainage information and any planning or reviewer comments.
What will I receive from the assessment and design work?
The agreed scope may include a feasibility note, investigation brief, calculations, layout or construction-detail input, alternative options and responses to technical comments.
What happens if monitoring or other investigation shows infiltration is unsuitable?
RIDA can set out suitable drainage alternatives for further assessment. Any controlled discharge, sewer connection or receiving-system proposal remains subject to site constraints, capacity and relevant permissions.
Discuss your high groundwater drainage constraints
Send your site address, proposed drawings and available ground data. These records let RIDA define the evidence gap, assessment scope, programme and fee.
Discuss your high-groundwater drainage constraints
Request a QuoteSchemes with wider surface-water issues may require drainage consultancy support.