What highway drainage actually is

When rain falls on a public road, it has to go somewhere. Most of it runs off the highway into gullies and drains that feed the public sewer, where it’s carried away and treated. Highway drainage is your share of the cost of doing that.

Because draining the roads benefits everyone connected to the network, the cost is spread across all connected properties as a line on the water bill. It’s held against your premises in the central market system, alongside your water, wastewater and surface water services.

Highway drainage vs surface water drainage

These two are behind most of the confusion on a water bill, and they sit right next to each other. The difference that matters is whose rainwater you’re paying to clear:

The practical takeaway: if you’re hunting for savings on the bill, surface water drainage is almost always where they are, because that’s the charge you can challenge when your own site doesn’t drain to the sewer. Highway drainage is the harder one to shift.

How highway drainage is charged

Highway drainage is usually a smaller, fairly fixed part of the bill rather than something that scales with the size of your site. The amount, and the way it’s applied, is set out in your wholesaler’s annual charges scheme, which is approved by the regulator, Ofwat. Some wholesalers fold it into the surface water charge, others list it on its own line.

However it appears, it’s tied to your property being connected to, and benefiting from, the public drainage network. That’s why it’s charged so consistently, and why it’s rarely removed.

Highway drainage is part of what wholesalers call site-area charging, the same system used for surface water. Your premises sits in a charging band based on its area, and you can be in a different band for highway drainage than for surface water. Every property connected to the public sewer contributes to it, which is why it’s applied so consistently.

Here’s the part that matters most: any drainage reduction you win applies to your surface water charge only, not your highway drainage. So even if you prove your site drains to a soakaway and get the surface water charge taken off, the highway drainage element stays. That’s the clearest reason to put your energy into the surface water charge, where the reduction actually lands.

Can you reduce or reclaim it?

Honestly, not often. Because highway drainage pays for a shared service that benefits every connected property, wholesalers very rarely take it off. It isn’t like surface water, where proving your rainwater never reaches the sewer can get the charge removed.

There are a couple of situations worth a look, though:

• Double counting. Check you’re not being billed twice for the same drainage through overlapping charges or duplicated records.
• A mis-recorded property. If your premises is recorded as using services it doesn’t, that record can be corrected.
• The bigger prize next door. While you’re in there, check your surface water charge, where the real savings usually sit.

A business water audit can review both charges together and flag anything that looks wrong.

Who pays highway drainage?

Like the rest of the water bill, the charge falls to the occupier of the premises. On a leased site the bill may be in the landlord’s name but recovered from the tenant through the lease or a service charge, so it’s worth knowing who actually carries it. It applies for as long as the property is connected and occupied.

Highway drainage and surface water drainage aren’t the same

These two charges get muddled constantly, and the names don’t help. Surface water drainage covers rainwater running off your own site into the sewer. Highway drainage covers the rain that falls on public roads and pavements and drains away through the same network. You can read the detail on surface water drainage if you want the distinction in full.

Both appear on business water bills, and both are based on assumptions rather than a meter. That’s exactly why they’re worth checking. An assumption that was wrong when your account was set up tends to stay wrong until someone questions it.

How to check a highway drainage charge on your bill

Highway drainage usually shows as a separate line under wastewater or drainage charges. If you can’t see it clearly, the first job is to confirm exactly who bills you, which our guide on finding your water supplier walks through.

From there it’s a question of whether the charge reflects your actual site. The way charges are built up is covered on our business water rates page, and if the numbers look off, that’s a reasonable basis to query it with your retailer.

Highway drainage FAQs