First Facts: Water-Filled Plastic Barriers

15 May 2025Appears in First Facts

Water-filled plastic barriers are a popular choice for managing site safety, crowd control, and temporary traffic systems—but how do they actually work, and what makes them effective? In this blog, we break down the key features that set them apart, offer expert setup tips, and answer the most common questions. Whether you're planning for construction, events, or road safety, read on to get clear, practical insights into choosing and using water-filled barriers effectively.

Key Features of Water-Filled Barriers

Our range of water-filled barriers has a range of key features, including:

Increased Stability When Filled: Water adds significant weight, greatly enhancing both impact resistance and overall stability for secure placement in high-traffic or high-risk areas.
High Visibility: Bright, highly visible colours combined with optional reflective strips ensure clear visibility in both daylight and low-light conditions.
Quick Set up or Removal: Lightweight when empty, these barriers are easy to transport and install, perfect for temporary use at construction sites, public events, or emergency roadwork zones.
Improved Safety: Designed to absorb and deflect impact, helping to reduce the risk of injury and damage during collisions or vehicle contact.

Our Top Tips

Fill for Maximum Stability

Always fill barriers to their recommended capacity to ensure they provide proper weight and resistance against impact or wind.

Connect Barriers Securely

Use the built-in interlocking system to link barriers together, creating a stable and continuous protective line.

12 Quick Questions to Master Water-Filled Barriers

What are water-filled plastic barriers made of?

Barriers are made from UV-stabilised Medium Density Polyethylene (UV MDPE), highly durable and ideally suited for areas where prolonged exposure to sunlight could degrade alternative materials.

How do water-filled plastic barriers work?

Water ballast is used inside the barriers to increase their wind resistance. Unfilled, Barriers are typically designed to interlock together, to form an unbroken, continuous ‘run’. When filled, accessories such as mesh or hoarding panels are typically available for increased visibility and security where required.

What is the weight of a water-filled plastic barrier?

Depending on the barrier chosen, weights can range from 4.6kg when empty up to 600kg when full. This allows for a wide range of applications from site demarcation to use in a live traffic, highway situation.

How are water-filled plastic barriers used?

Barriers have a multitude of uses, from segregating specific areas in car parks or school playgrounds to enclosing construction or utility sites. They are also often used on the highway, where operatives are road working.

Can water-filled plastic barriers withstand high winds?

Many barriers on the market are independently tested and certified to withstand winds. Some barriers, depending on weight, can withstand winds in excess of 77mph, even with a 2 metre mesh panel included.

How do you fill and empty water-filled plastic barriers?

Barriers can be filled easily by mains or bowser water supply through the large, easy-fill caps. Drainage is through drain holes at the base of each barrier, fitted and sealed with a bung, which can be removed with a dedicated tool or a simple screwdriver

Can water-filled plastic barriers be used in freezing temperatures?

Water-filled barriers, by their very nature, can be affected by freezing temperatures. As the ballast doesn’t fill the barrier, there is room for water’s expansion during freezing. Steps can be taken to mitigate potential damage when the water inside barriers freezes and expands. It is not recommended to use anti-freeze products inside barriers, which could pose a toxic threat to the surrounding environment as well as cause potential damage to the barrier structure. A simple and cost-effective solution is to add salt to the water, which lowers the freezing point.

How are water-filled plastic barriers transported?

Barriers are transported either on a standardised or oversized pallet and shrink-wrapped or banded together for safety during delivery. Once on site, barriers are easily manoeuvred into position by either a one- or two-person team without the need for heavy machinery before water filling. The products also have fork slots for convenient movement. It isn’t recommended that barriers be moved while containing ballast.

Are water-filled plastic barriers eco-friendly?

Many barriers are designed to be recyclable and minimise the overall lifetime impact on the environment.

How long do water-filled plastic barriers last?

Barriers, particularly those that are rotationally moulded, are designed to be durable and long-lasting under normal working conditions. The lifespan of barriers will vary depending on use and care.

Are water-filled plastic barriers effective for safety?

Barriers are designed as a visual deterrent when marking a site boundary, restricting access, and increasing security, particularly when paired with top panels. When it comes to road safety, certain barriers are independently crash tested and approved to British Standards.

Can water-filled plastic barriers be stacked or connected?

Most barriers can be stacked for both easy storage and transportation. This makes them a very cost-effective solution.

Want to keep spaces safe and clearly divided? Try Water-Filled Barriers.

At First Fence, we offer a wide range of water-filled barriers to suit all types of projects, from light-duty site demarcation to heavy-duty roadside safety. Our selection includes trusted solutions like the Evo Barrier, Novus Barrier, RB200, RB22, GB2, and many more. Whether you need barriers for construction, traffic management, or public events, our team is here to help you find the right product for the job. Get in touch today for expert advice or a no-obligation quote.