Is Your Silage Storage Meeting SSAFO Regulations?

SSAFO rules, or the storing ‘Silage, Slurry and Agricultural Fuel Oil’ rules are set out by the government to cover the storage and handling of all 3 substances. With the requirement for silage pits to be up to SSAFO rules for Capital Grant applications and the ongoing Environment Agency farm audits, does your silage storage meet the SSAFO rules?

New and substantially changed stores must meet SSAFO rules. Silage pits built pre-March 1991 are exempt, UNLESS there has been a change structurally i.e., capacity has increased, or the store has been relocated. See below a basic overview of the SSAFO rules to see if your store meets requirements.

Silage silo requirements:

  • Must have an impermeable base, which complies with British standards (concrete and hot rolled asphalt bases), extending beyond the walls.
  • Impermeable drainage collection channels around outside of silo, with flow going into effluent tank.
  • Effluent tanks must:
    • If above ground, be constructed to resist attack from silage effluent for 20 years with maintenance
    • If below ground, be impermeable for at least 20 years without maintenance
    • Manufacturers guarantee must be available on inspection
  • Capacity
    • Minimum capacity for effluent tanks is at least 2 days storage at peak flow 

Silo capacity

Minimum effluent tank capacity


20 litres per m3


30m3 plus 6.7 litres/m3 of silo capacity over 1,500m3

Storage baled silage
Specially constructed bases are not required if bales are wrapped in impermeable membrane or bags. Efforts must be made to ensure there is no runoff into watercourse with storage being a minimum of 10m away from inland and coastal waters.

Field silage
Silage storage can be stored in field without walls/earth banks or construction if topsoil is not disturbed. Sites must be suitable, and any effluent contained with drainage. Environment Agency must be contacted 14 days before site is used.

If you are starting work on your silage store, you must tell the Environment Agency at least 14 days before construction begins, make sure you don’t pollute surrounding rivers or water courses and check if you need planning permission.

If you would like to discuss this further or find out more about the Slurry Infrastructure Grant, please contact Emily on 07944 680469 or e-mail