Koi and Wildlife Pond Liners: All Guides
Quick answer: Koi ponds are deep and heavily stocked, so they need a strong, fish-safe liner and careful underlay; heavier EPDM and butyl are common choices. Wildlife ponds benefit from gently sloping edges and shallow margins so animals can get in and out, and flexible liners follow those contours best.
- Use a fish-safe liner and a geotextile underlay
- Deep koi ponds need more liner: add 2 x max depth to each dimension
- Wildlife ponds need shallow, sloping margins
- Flexible EPDM and butyl follow curves and shelves best
- EPDM is sold in 0.75mm and 1.0mm listings
Last reviewed: 3 October 2026 · Reviewed by the PondLinersco.co.uk team
Start here
- Koi pond liner guide (professional)
- Wildlife pond liner guide
- Koi Pond Professional Kit
- Wildlife Pond Starter Kit (EPDM)
- Koi pond net cover
All guides (9)
- Fish-Safe Pond Liner UK — Which Types Are Certified Safe for Fish? — EPDM and butyl rubber, and food-grade HDPE, are fish-safe liner types; standard PVC can leach plasticisers.
- How to Build a Koi Pond UK — Step-by-Step Expert Guide 2025 — Plan for at least 1.2m depth (1.5-1.8m preferred), around 1,000 litres per adult koi and filtration with a bottom drain.
- How to Create a Wildlife Corridor with Pond Liners UK — Ecological Design Guide — A wildlife corridor links ponds through wet margins, ditches, hedgerows and damp grassland so species can move between them.
- Is Pond Liner Fish Safe UK — What Certifications Actually Mean — Pond-grade EPDM, butyl and HDPE are chemically inert and generally considered fish safe; PVC is safe only when made with fish-safe plasticisers and stabilisers.
- Pond Liner for Ducks & Waterfowl UK — Safe Materials & Installation Guide — We recommend pond-grade EPDM or butyl rubber laid over geotextile underlay, with 1.0mm EPDM preferred where duck claws cause wear.
- Pond Liner for Koi Ponds UK — Depth, Safety & Material Requirements — Koi ponds need at least 1.2m depth, ideally 1.5m, and a smooth, inert liner such as EPDM or butyl rubber, which contain no plasticisers.
- Pond Liner for Schools & Educational Ponds UK — Safety & Specification Guide — No law bans school ponds, but schools must risk-assess them under general health and safety duties.
- Pond Liner for Stepping Stone Ponds UK — Ecological Network Design & Specification — Stepping stone ponds are mostly shallow (0.1-0.5m, deepest 0.5-0.8m) fish-free wildlife ponds with gently sloping margins.
- Wildlife Pond UK – Complete Build Guide & Best Liner for Wildlife — Build a wildlife pond with an irregular shape, gently sloping sides (about 1:3, or 20°) and a beach to ground level, shelves at 10–20cm and a zone at least 60cm deep.
Other topic hubs
- How to Choose a Pond Liner
- Pond Liner Sizing
- Pond Liner Installation
- Pond Liner Materials
- Pond Liner Underlay
- Pond Liner Repair and Leaks
- Commercial and Large Pond Lining
Need help choosing? Contact our team or see the pond liner hub.