SEPA Water Pollution Guidance Scotland | Spill Control & Compliance

In Scotland, the Scottish Environment Protection Agency (SEPA) expects sites to prevent water pollution from spills, leaks, washdowns and contaminated runoff. If you store, handle, transfer or dispose of liquids, this guidance matters whether you are in manufacturing, transport, warehousing, facilities management, agriculture, construction, utilities or public sector estates.

This page answers the practical questions we hear most often and turns SEPA water pollution guidance into clear spill control actions: bunding, spill kits, drain protection, drip trays, safe transfer, incident response and documentation.

Question: What does SEPA mean by water pollution on a working site?

Solution: Water pollution is not limited to major chemical releases. SEPA treats a wide range of substances and activities as potential pollution when they can enter surface water (rivers, burns, lochs), groundwater, coastal water, private water supplies, or the drainage network. Typical pollution pathways include:

Surface water drains that discharge to a watercourse (often labelled "surface" or "storm").
Foul drains (to sewage treatment) where harmful liquids can still cause compliance issues, treatment disruption, or trade effluent breaches.
Ground penetration via unmade ground, cracked slabs, service ducts, soakaways and gully pots.
Runoff from yards during rain, especially where oils, silt, detergents or chemicals are present.

Common site pollutants include oils and fuels, coolants, solvents, paints, acids/alkalis, cleaning chemicals, food and drink waste, and even silt. Different spill types require different controls. See our overview of spill scenarios here: Types of spills.

Question: Do I need bunding and secondary containment to meet SEPA expectations?

Solution: In most cases, yes. Bunding and secondary containment are the frontline controls for preventing loss of containment reaching drains or ground. A practical approach is to match containment to the risk:

Fixed tanks and IBCs: use bunded areas, bunded pallets or hardstanding containment where liquids are stored long term.
Drums and small containers: use spill pallets, drip trays, bunded shelving or bunded cabinets.
Transfers and decanting: carry out in a contained zone with drip trays, absorbents, and drain covers within reach.
Mobile plant and vehicles: consider refuelling mats, drip trays and spill kits on vehicles.

Containment is not just about storage. Many pollution incidents occur during delivery, connection/disconnection, valve operation, or when a container is moved. Secondary containment should cover these activities where practicable.

Question: What should we do about drains to prevent pollution incidents?

Solution: Treat drains as the fastest route to a reportable incident. A strong SEPA-aligned approach is:

Know your drainage: identify and label surface versus foul drainage, locate outfalls, interceptors, and high risk gullies.
Keep drain protection ready: position drain covers, drain mats, socks and absorbent booms where a spill could reach a gully quickly.
Control yard runoff: good housekeeping, prompt clean-up, and planned washdown so detergents and contaminants are not flushed into surface water drains.
Use isolation where available: penstocks or shut-off devices can help, but only if staff know where they are and can deploy safely.

Drain protection is most effective when combined with spill containment and trained first response so that liquids are stopped at source and also blocked from entering gullies.

Question: Which spill kit do we need for Scottish water pollution prevention?

Solution: Choose spill kits by the liquids you handle, where you work, and the likely spill size. For SEPA water pollution risk, fast deployment matters as much as capacity. A robust setup usually includes:

Oil-only absorbents for hydrocarbons (fuels, oils) including outdoor use in wet conditions.
Chemical absorbents for acids, alkalis, solvents and unknown liquids.
General purpose absorbents for water-based fluids and maintenance spills.
Drain protection (covers, socks, booms) to protect surface water drains.
PPE and waste bags to support safe clean-up and compliant disposal.

Site examples:

Warehouse with loading bays: oil-only spill kit at each bay, drain covers near external gullies, drip trays for damaged pallets.
Engineering workshop: general purpose kit for coolants, oil-only for lubricants, chemical kit near chemical storage, plus drip trays under machines.
Facilities and estates teams: compact vehicle spill kits for first response, plus a larger central kit in the yard and drain protection at known hotspots.

Question: What is a practical spill response plan SEPA would expect?

Solution: A credible spill response plan focuses on prevention, rapid control, and clear escalation. A workable structure is:

Stop: if safe, stop the source (upright container, close valve, isolate pump).
Contain: deploy absorbent socks/booms and use drip trays or temporary containment to prevent spread.
Protect drains: use drain covers or mats immediately where there is a pathway.
Recover and clean: use suitable absorbents, then clean the area without washing contaminants into drains.
Dispose: bag and label waste absorbents and contaminated materials for correct disposal.
Report and review: record the incident, investigate root cause, and update controls to prevent recurrence.

Make sure the plan is matched to your operations: deliveries, decanting, drum handling, IBC tapping, outdoor storage, waste areas, and maintenance tasks. Position spill control products where they are needed, not just where they are convenient.

Question: How do we show compliance and due diligence in Scotland?

Solution: SEPA will look for evidence that you understand your risks and have appropriate controls. Practical evidence includes:

Drainage map and marked gullies/outfalls with surface water drains clearly identified.
Inspection records for bunds, drip trays, IBCs, drums, valves, hoses and interceptors.
Spill kit checks (stock levels, locations, seal checks, replacement after use).
Training records showing staff know how to deploy absorbents and drain protection quickly.
Incident log with actions taken and corrective measures.

Good documentation supports environmental compliance, ISO 14001 objectives, contractor management, and insurance expectations. It also reduces the chance that a small spill becomes a water pollution incident.

Question: What are common mistakes that lead to SEPA water pollution incidents?

Solution: Avoid these frequent gaps:

Unlabelled drains leading to accidental discharge to surface water.
Spill kits stored too far away from loading/unloading points and chemical stores.
No drain protection or it is buried in a cupboard and not deployable in seconds.
Washdown practices that push oils, silt and detergents into yard drains.
Inadequate secondary containment for IBC taps, pumps, and decanting areas.
Waste handling weaknesses such as leaking skips or damaged containers stored outdoors.

Question: Where can I find the official SEPA guidance?

Solution: Use SEPA as the primary source for water pollution prevention expectations and incident reporting advice. Start here:

SEPA (Scottish Environment Protection Agency) - guidance and resources for pollution prevention and environmental compliance in Scotland.

For spill scenarios and practical controls, use our guidance here: Types of spills.

Question: What should we do next on site?

Solution: If you want to reduce SEPA water pollution risk quickly, prioritise these actions this week:

Walk the site and identify all drains, gullies and likely spill pathways.
Check that spill kits match the liquids handled (oil-only, chemical, general purpose) and are located at hotspots.
Add drain protection at external gullies near loading bays, tanks, chemical stores and waste areas.
Review bunding and drip tray coverage for storage and transfer activities, not just static storage.
Run a short spill response drill and record improvements.