A water filled barrier (also called a water-ballasted barrier or plastic jersey barrier) is a hollow plastic modular barrier that is filled with water on-site to provide weight, stability and vehicle containment. Lightweight when empty (15–25kg) but weighing 300–1000kg when filled, water filled barriers are widely used for temporary traffic management, event safety, construction sites and hostile vehicle mitigation at public events in the UK.
What is a Water Filled Barrier? — Complete UK Guide
Water filled barriers represent one of the most significant innovations in traffic management and event safety of the past 30 years. Before their widespread adoption, providing meaningful vehicle containment in temporary situations required either precast concrete barriers (heavy, requiring crane deployment) or a proliferation of cones and signs with no actual physical barrier to errant vehicles. The water-fillable plastic barrier solved both problems — combining the containment capability of heavy concrete with the deployment flexibility of a lightweight, stackable product.
How Water Filled Barriers Work
The basic principle is simple: an empty plastic shell weighing 15–25kg can be carried by two people and stacked for transport. Once positioned on-site, a fill hole in the top (typically covered by a rubber plug or cap) allows the barrier to be filled with water using a standard hose or pump. Filled, the barrier can weigh 300kg (for a 1m unit) to over 1,000kg (for a 2m unit) — providing substantial inertia against vehicle impact.
Multiple barriers can be linked together using interlocking fins, hooks or connecting pins to create continuous barrier runs of any required length. The interlocking prevents gaps opening up between adjacent barriers under vehicle load. At the end of the deployment, the water can be drained on-site (via a drainage plug) and the empty barriers restacked for transport and reuse.
Water Filled Barrier Dimensions and Capacity
| Size | Height | Width (base) | Weight Empty | Weight Full |
|---|---|---|---|---|
| 1m barrier | 800mm | 500mm | 15–18kg | 250–350kg |
| 1.5m barrier | 800mm | 500mm | 22–28kg | 400–500kg |
| 2m barrier | 1000mm | 600mm | 30–45kg | 700–1000kg |
| Tall 2m barrier | 1200mm | 600mm | 40–55kg | 800–1200kg |
Water Filled Barrier Applications in the UK
Temporary Traffic Management (TTM) and Roadworks
Water filled barriers are the most widely used Chapter 8 compliant barrier type for UK roadworks and temporary traffic management. They separate live traffic from roadworks zones, channelise traffic through lane closures, and provide physical protection for road workers and plant. Their ability to be deployed rapidly (a team can typically position and connect 50 barriers per hour) and removed similarly quickly makes them ideal for frequently moved contraflow schemes or short-term roadworks.
Hostile Vehicle Mitigation (HVM) at Events
Following vehicle-borne attack incidents at public events in Nice (2016, 86 fatalities), London Bridge (2017) and Stockholm (2017), Counter Terrorism Security Advisors (CTSAs) began recommending water filled barriers as a cost-effective vehicle mitigation solution for outdoor events and crowded places. While not certified to PAS 68 or IWA 14-1 standards (which require permanent foundations), filled water barriers provide meaningful vehicle containment when properly interlinked and positioned. UK police guidance from NaCTSO and Project Servator includes water filled barriers in their recommended approach for event HVM.
Construction Site Perimeters
Water filled barriers create robust, visible construction site perimeters protecting the public from site activities. They are often used at the base of Heras (mesh panel) fencing — the barriers prevent vehicles driving into or through the base of the fence while Heras provides height. This combination is the standard approach for securing major UK construction sites adjacent to public highways.
Flood Defence
Some water filled barrier types are specifically designed for temporary flood defence — they are positioned in a line perpendicular to the flood flow and filled with water from the flood itself (using a submersible pump) or from an external source. Used by the Environment Agency, local councils and commercial flood response teams for emergency flood protection of property.
Car Park and Access Control
Orange water filled barriers are increasingly used as removable access control barriers in car parks, emergency access routes and private roads — where their ease of repositioning offers flexibility that fixed barriers cannot match.
Chapter 8 Compliance for Water Filled Barriers
Water filled barriers used in UK temporary traffic management must comply with Chapter 8 of the Traffic Signs Manual. Chapter 8 specifies performance requirements for traffic barriers including impact performance, retroreflective requirements, and dimensional constraints. Barriers Co's water filled barriers are supplied with CE marking and meet Chapter 8 requirements. Documentation for Streetworks permit applications is available on request.
Water Filled Barriers vs Concrete Jersey Barriers
| Feature | Water Filled Plastic | Concrete Jersey Barrier |
|---|---|---|
| Weight empty/installed | 15kg / 300kg (1m) | 900kg (1.8m fixed) |
| Deployment method | Manual, no crane | Crane required |
| Containment when filled | Good (250–350kg/m) | Excellent (500kg/m+) |
| Reusable | Yes, many times | Yes, but heavy to move |
| Suitable for HVM events | Yes (with CTSA advice) | Yes |
| Cost | £200–£500 per unit | £300–£600 per unit (plus crane hire) |
Buy Water Filled Barriers from Barriers Co
Barriers Co supplies 1m, 1.5m and 2m water filled plastic barriers in orange and white, with reflective markings, connecting pins and delivery across the UK. Also available: tall 1200mm height barriers for enhanced vehicle and pedestrian segregation. Volume pricing available for event companies, local authorities and civil engineering contractors. Contact us for a free quote.