Water bills are a necessary expense for any business, but have you ever stopped to really examine what you’re being charged for? While most businesses are familiar with paying for the water they use and the sewerage services that remove it, many are unaware of additional hidden charges that could be costing them thousands of pounds each year. One of the most overlooked yet significant charges is the surface water drainage fee, which, in some cases, can be significantly higher than expected—especially when combined with highways drainage charges.

What are surface water drainage and highways drainage charges?

At first glance, your water bill may seem straightforward. However, surface water drainage and highways drainage charges can cause confusion for many businesses. Simply put, these charges are levied to cover the cost of managing the rainwater that falls on your property—and in some cases, on the surrounding area. Here’s where it gets tricky: businesses are charged not only for rainwater that falls directly on their premises, such as rooftops and car parks, but also for the rainwater that falls on public roads and motorways around them. This can mean paying for something you might not even have control over.

Why is this charged, and how does it differ by location?

Surface water drainage occurs when rainwater falls on a property and drains away.

Most rainwater falling on properties drains into public sewers owned by the ten water and sewerage companies in England and Wales. These companies are responsible for removing and processing this rainwater. If rainwater drains from your property into a public sewer, you will be charged for surface water drainage through your sewerage bill.

You will pay for surface water drainage in your bill in one of the following ways:

• A fee in the standing charge
• A volumetric charge based on the amount of water you use
• A charge based on the rateable value of your property
• Through a charge related to the type of property you live in

If rainwater does not drain from your property into a public sewer, because you have a soakaway or similar, you may be entitled to a surface water drainage rebate. Your company provides information about the qualification criteria and the level of any rebate in its charges scheme, which is published on its website.

The way businesses are charged varies depending on which water company area they are in. Basically businesses in the South will have surface water drainage and highways drainage are typically embedded in their water bill. Businesses in the north Birmingham, will have charges are listed separately as added costs normally based on surface area of the property. So, depending on your location, you may see a charge for surface water drainage and a highways drainage charge, both calculated based on your property and its proximity to the surrounding infrastructure. Where the charges are separate they are often banded with costs increasing in steps depending on area.

The problem is that the way these charges are assessed can feel arbitrary and lack transparency. For example, water companies often use mapping tools like Google Maps to assess your area, determine the size of your property, and calculate the corresponding drainage fees. But this doesn’t take into account the specific features of your property that could reduce the amount of rainwater runoff—things like permeable car parks, grassy areas, or even green roofs.

How to reduce these costs

The good news is that there are often ways to reduce these hidden drainage charges. Firstly, you should check the area calculations, often these are not that accurate and sometimes a simple calculation can change your charging band and result in a reduction of thousands of pounds a year.

If your business has a permeable car park, wooded areas, or green space that allows rainwater to naturally soak into the ground, you may be able to lower your surface water drainage fee. The key is to identify how much of your property actually contributes runoff into the sewer, as you are only supposed to be charged for the areas that catch rainwater. If rainwater does not drain from your property into a public sewer, because you have a soakaway or similar, you may be entitled to a surface water drainage rebate.

One of the most effective ways to manage this is through rainwater harvesting. By installing systems that capture and reuse rainwater, you can reduce the amount of runoff from your property and lower both your surface water drainage and sewerage charges. In fact, in some cases, businesses that invest in rainwater harvesting have seen savings of tens of thousands of pounds each year.

The importance of conducting a water bill audit

If this all sounds complicated, that’s because it is. The billing process for surface water drainage and highways drainage is not straightforward, and many businesses are simply unaware of the potential for savings. This is where performing an audit of your water bills comes in. Start by laying out your water bills and looking closely at the charges related to surface water drainage and highways drainage. Ask yourself questions like:

• Why am I being charged for rainwater that falls on roads and motorways around my business?
• Is it embedded in the bill or listed as an additional charge?
• How much of my property contributes to rainwater runoff?
• Could I reduce these charges by making improvements to my car park or other outdoor spaces?

The savings from a thorough audit and any subsequent changes could be significant, especially if you’re in an area where the highways drainage charge is added on top of your regular surface water drainage charge.

Why don’t more businesses know about this?

So, why are so many businesses unaware of the potential for significant savings on their water bills? The reality is that this issue is complicated, and water companies don’t always make it clear how these charges are calculated. As a result, many businesses may not even realize that they’re paying for water runoff they don’t control or that could be reduced through simple modifications.

Take action and save

The bottom line is that surface water drainage and highways drainage charges are a hidden cost that could be costing your business more than you realize. But with a little effort, you can uncover potential savings by performing a thorough audit of your water bills and making changes to your property to reduce your runoff. Whether it’s through installing permeable surfaces or investing in rainwater harvesting, or simply applyinhg for the right discounts from your water company, the savings could be substantial—and it all starts with asking the right questions and understanding your bills.

Don’t let these hidden costs slip by unnoticed. Take the time to review your charges and explore ways to reduce your drainage fees. Your business—and your bottom line—will thank you.