On this page
What does SSAFO 2018 actually require?
SSAFO 2018 sets minimum standards for the construction, location and management of silage clamps, slurry stores and agricultural fuel oil tanks in England. New or substantially altered installations must be designed to a 20-year life, sited to minimise pollution risk, notified in writing to the Environment Agency, and inspected on demand.
The regulations are enforced by the Environment Agency under powers in the Water Resources Act 1991. They sit alongside the Farming Rules for Water (SI 2018/151) and, in NVZs, the Nitrate Pollution Prevention Regulations. Cross-compliance was withdrawn in England at the end of 2023 and the Sustainable Farming Incentive has no cross-compliance conditionality — but SSAFO compliance remains a legal requirement in its own right, enforced directly by the Environment Agency regardless of any scheme payments.
Older installations built before 1 March 1991 are partially grandfathered, but any substantial alteration triggers SSAFO 2018 in full. "Substantial" includes changing the footprint, increasing capacity by more than 10%, or replacing the structural elements. WCCP supplies SSAFO-ready precast across the agricultural range — slurry storage panels, silage clamp walls and slurry channels & covers.
How do I calculate slurry storage volume?
Use the AHDB slurry calculator. Multiply daily slurry production per head by livestock numbers by storage days required (5–6 months), then add rainwater inputs and a safety factor. A 200-cow dairy in an NVZ typically needs around 3,500–4,500m³ (~123,600–158,900 cu ft) of storage to comply.
| Livestock type | Slurry / day | 5-month storage | 6-month storage |
|---|---|---|---|
| Dairy cow (Holstein, housed) | 53 litres (11.7 UK gal) | ~8.0 m³/cow (283 cu ft) | ~9.7 m³/cow (343 cu ft) |
| Dairy cow (Jersey, housed) | 38 litres (8.4 UK gal) | ~5.7 m³/cow (201 cu ft) | ~6.9 m³/cow (244 cu ft) |
| Beef finisher (500kg) | 40 litres (8.8 UK gal) | ~6.0 m³/head (212 cu ft) | ~7.3 m³/head (258 cu ft) |
| Suckler cow + calf | 35 litres (7.7 UK gal) | ~5.3 m³/head (187 cu ft) | ~6.4 m³/head (226 cu ft) |
| Pig (finishing, 100kg) | 7 litres (1.5 UK gal) | ~1.05 m³/head (37 cu ft) | ~1.27 m³/head (45 cu ft) |
Add rainfall capture from any open store: roughly 1m³ per m² of surface area per metre of regional annual rainfall. Devon averages 1.0–1.2m/year (about 3'3"–3'11" per year).
What structural standards apply to SSAFO stores?
Slurry stores and silage clamps must be structurally designed by a chartered engineer to relevant British Standards for agricultural buildings and liquid-retaining structures. Structural design must demonstrate the 20-year design life with reasonable maintenance.
In practice that means a chartered structural engineer signs off on panel thickness, reinforcement, post or buttress design, foundation design and joint detail, with concrete grade and cement type (typically sulphate-resisting) chosen for slurry duty. Our products are manufactured in compliance with applicable British Standards — for information regarding the specific standards applicable to a particular product, please contact us.
The Environment Agency does not certify designs, but it can challenge any installation it believes is non-compliant. Keeping the engineer's calculations and a copy of the WQE1 form on file is worth doing — both are routinely requested at inspection.
How far from a watercourse must a slurry store sit?
SSAFO 2018 requires a minimum 10m (32'10") separation between any slurry, silage or fuel oil installation and any inland or coastal water. The EA may require additional separation if groundwater, springs, boreholes or land drains are within the wider area.
"Inland water" includes rivers, streams, ditches, ponds, and any feature that drains to a watercourse — even a dry ditch that flows in winter. Land drainage outfalls and field drains within the catchment of the store are also considered.
We recommend a desktop check (Magic Map for SSSIs and SPZs, plus a site walk for ditches and land drains) before agreeing a store position. Moving a planned store 5m (16'5") to clear a ditch is far cheaper than building it and being told to remove it.
What freeboard is required?
Freeboard requirements vary by store type under the SSAFO regime — earth-banked lagoons carry a different allowance to rectangular precast or circular stores, and the governing figure depends on store geometry and rainfall exposure. Silage clamps require an effluent collection capacity sized to the regulations.
Freeboard is structural margin and a pollution buffer in one. It allows for agitator disturbance, foam build-up, mistimed emptying and unexpected rainfall ingress. It also keeps the slurry below any bolt-down equipment or mixer access points where joints are often the first thing to fail.
We size the parapet height on every WCCP slurry store to the freeboard your store type requires, and we mark a depth indicator at that level so the operator can see at a glance whether emptying is overdue. Check the current gov.uk SSAFO guidance for the governing freeboard figure for your store, or ask us to confirm against your design.
How do I notify the Environment Agency (WQE1)?
Submit form WQE1 to the Environment Agency at least 14 days before any construction, substantial enlargement or substantial reconstruction of a slurry, silage or fuel oil installation. Include drawings, location plan, capacity calculations and the engineer's design statement.
The 14-day window gives the EA time to comment, request changes or arrange an inspection. Most submissions go through without challenge if the structural design is sound and the distances and freeboard meet SSAFO. The EA can extend the period or require modifications if it identifies a pollution risk.
Submit electronically via the gov.uk WQE1 portal. Keep the acknowledgement email on file — it is your evidence of compliance with the notification obligation.
What are the penalties for SSAFO non-compliance?
Breach of the SSAFO Regulations is a criminal offence carrying an unlimited fine on summary conviction — the £5,000 magistrates' cap was abolished in 2015. The EA can also issue enforcement notices, prohibition notices and recover clean-up costs from the operator.
In practice the most common enforcement path is an EA officer visit, a written advisory letter, then an enforcement notice with a deadline. Prosecutions usually follow either a pollution incident or repeated refusal to comply with an enforcement notice.
Insurance cover for environmental liability is increasingly excluding non-compliant installations. Lenders financing slurry infrastructure routinely require evidence of SSAFO compliance as a drawdown condition.
SSAFO 2018 14-point compliance checklist
Tick all 14 before construction starts.
- Storage capacity calculated against AHDB livestock slurry production figures
- 5 months minimum (cattle) or 6 months (pig/poultry, NVZ, or SIG-funded)
- Rainfall capture added to capacity calculation for open stores
- Minimum 10m from any inland or coastal water
- SSSI, SPZ and borehole desktop check completed (Magic Map)
- Land drains and field drainage outfalls identified and isolated
- Structurally designed to relevant British Standards by a chartered structural engineer
- 20-year design life specified in writing
- C40/50 sulphate-resisting concrete (CEM III/B or CEM IV) for slurry duty
- Freeboard sized to store type and demonstrated against rainfall exposure (check current SSAFO guidance)
- Hydrophilic waterstop and slurry-rated sealant at every joint
- Form WQE1 submitted to Environment Agency at least 14 days before construction
- EA acknowledgement email retained on file
- Inspection and maintenance plan documented for the 20-year life
Building a SSAFO-compliant store?
We manufacture and deliver precast for SSAFO 2018-compliant slurry stores, silage clamps and effluent tanks across the South West. Send us your livestock numbers and we'll come back with a capacity check, panel schedule and fixed price.