Project Snapshot

Application: Adoptable foul water pumping station
Scale: Serving 56 residential dwellings
Location: Witheridge, Devon
Adoption Body: IWNL
Pump Configuration: Twin submersible sewage pumps with telemetry and flow monitoring
Result: Construction issue design completed in accordance with IWNL Design & Construction Guidance

Project Overview

Advantage Pumping Solutions was appointed by Allison Homes SW Limited to design and deliver an adoptable foul water pumping station for the Witheridge Phase 2 residential development in Devon.

Designed in accordance with the latest IWNL addendum to the Design and Construction Guidance (DCG), the pumping station forms a critical part of the site’s foul drainage infrastructure, providing reliable wastewater management for 56 new homes while ensuring full compliance with adoptable standards.

The project required a technically robust solution capable of meeting strict emergency storage, retention time, telemetry, and hydraulic performance requirements while supporting a smooth approval and construction process.

Why We Won the Project

Allison Homes selected Advantage Pumping Solutions for our:

• Proven expertise in adoptable pumping station design for IWNL and other NAV providers
• In-depth understanding of DCG technical requirements and approval processes
• Ability to provide fully coordinated design support throughout changing site layouts and drainage revisions
• Track record of delivering compliant, adoption-ready systems with practical construction support

Our responsive approach enabled design amendments to be incorporated efficiently throughout the project lifecycle as the development evolved.

What We Delivered

Advantage Pumping Solutions provided the complete foul pumping station design package, including:

• Full adoptable foul water pumping station design tailored to serve 56 new dwellings
• Carefully engineered system capacity to meet IWNL and DCG compliance requirements
• Emergency storage and rising main design developed to support reliable long-term operation
• Selection of high-performance Grundfos pumping equipment for efficient and dependable performance
• Integrated telemetry and flow monitoring to support operational visibility and adoption requirements
• Coordinated technical support throughout design revisions and approval stages to keep the project progressing smoothly

Installation & Timeframe

Design & Approvals: 2023 (including multiple revisions to accommodate updated drainage layouts and additional plots)
Delivery Status: Delivery Status: Final construction issue design completed and prepared for implementation
Outcome: System designed to support efficient installation, reliable operation, and future IWNL adoption

Challenges We Overcame

Evolving Site Layout & Drainage Revisions

Throughout the design process, the drainage layout and site configuration changed multiple times, including revisions to levels and the addition of two extra plots late in the programme.

Our engineering team responded quickly to each revision, updating hydraulic calculations, storage requirements, and pump station layouts while maintaining compliance with IWNL adoption standards.

Emergency Storage & Retention Compliance

The pumping station required substantial emergency storage capacity while also maintaining acceptable foul water retention times to prevent septicity risks.

Through careful hydraulic modelling and wet well sizing, we designed a solution that:

• Achieved the required 8,960 litres of emergency storage
• Maintained rising main purge intervals well below the 6-hour septicity threshold
• Eliminated the need for additional septicity control equipment

This reduced complexity, installation costs, and future maintenance requirements for the client.

The Outcome

Advantage Pumping Solutions delivered a fully coordinated adoptable foul water pumping station design that aligned with IWNL requirements while supporting the wider development programme.

Key outcomes included:

• Adoption-ready foul water pumping station designed in accordance with IWNL and DCG standards
• Design revisions incorporated efficiently without delaying project progress
• Emergency storage and hydraulic performance requirements achieved from the outset
• System engineered for reliable long-term operation and simplified future maintenance
• Prepared for efficient installation, commissioning, and future adoption

Let's Talk

Need an adoptable pumping station partner who can manage technical complexity while keeping your project moving?
Contact Advantage Pumping Solutions today.