Surface water drainage responsibility is becoming a more significant issue for businesses and property managers across the UK. As rainfall becomes heavier and more frequent during the autumn and winter months, many commercial sites experience standing water, blocked gullies and localised flooding. In most cases, these problems occur not because of extreme weather, but because the site’s surface water system is not being maintained or monitored effectively.

Understanding who is responsible for managing surface water is essential for preventing disruption. Property teams often assume that water companies handle all drainage issues, but this is rarely the case. Much of the drainage infrastructure on private land, including gullies, channels, downpipes and onsite surface water pipework, must be managed by the business or property owner. When this responsibility is overlooked, the risk of flooding and operational downtime increases significantly.

This blog sets out a clear explanation of what surface water drainage is, who is responsible for maintaining it and why taking a proactive approach is vital for keeping sites safe, compliant and free-flowing during periods of heavy rain.

What is surface water drainage? A clear, practical explanation

Surface water refers to rainwater that collects on roofs, pathways, car parks, loading areas and other hard surfaces. Once it lands, it must be directed away from the site through a network of gullies, channels, gutters, downpipes and underground pipework.

This system is designed to prevent surface water from pooling, flooding buildings or overwhelming the foul water system. When working correctly, surface water drainage moves water quickly and safely into the appropriate outfall, whether that is a public surface water sewer, a soakaway or an approved watercourse.

It is important to understand the distinction between surface water drainage and foul water drainage. Foul water systems handle wastewater from toilets, sinks and appliances. These networks must remain separate. When surface water enters the foul system or vice versa, it increases the risk of flooding, blockages and compliance issues.

Who is responsible for surface water drainage?

This is one of the most common questions asked by facilities teams and property managers. The answer is not always straightforward, but the principles are clear.

Property owners

In most cases, the business or property owner is responsible for the surface water drainage system on their land. This includes:

  • Gullies and yard drains
  • Channels and linear drainage
  • Roof gutters and downpipes
  • All private surface water pipework until it reaches the boundary

These assets must be maintained to prevent blockages, flooding and water ingress.

Facilities managers and tenants

Where businesses lease premises, responsibilities often sit with the tenant for day-to-day maintenance such as clearing gullies or reporting issues. Larger structural repairs may remain with the landlord, depending on the lease agreement.

Local authorities

Councils are responsible for:

  • Highway gullies
  • Road drainage
  • Some public footpaths

However, this does not extend to private car parks, access roads or estate roads owned by businesses.

Water companies

Water companies typically only manage:

  • Public surface water sewers
  • Combined sewers
  • Assets beyond the property boundary

They are not responsible for clearing private blockages or managing drainage on private land.

Understanding where responsibility lies helps ensure the right organisation is contacted when issues arise and prevents delays during urgent situations.

Common surface water drainage issues on commercial sites

Surface water drainage problems often start small but can develop quickly if not addressed. Common issues include:

  • Standing water in car parks or yard areas caused by blocked gullies or poor site levels
  • Gullies filled with silt, leaves or debris following autumn leaf fall
  • Slow drainage after rainfall indicating restricted flow or pipe obstruction
  • Water pooling near building entrances which increases slip risks and can cause internal flooding
  • Damaged or collapsed pipes preventing water from leaving the site
  • Overflowing manholes during heavy rain if the system is overloaded

These issues are not just inconvenient; they can pose safety risks, reduce operational efficiency and cause structural damage if left unresolved.

How surface water drainage problems lead to operational disruption

When surface water cannot drain away correctly, the impact on a business can be significant.

  • Car parks and access routes may become unusable.
  • Delivery and service yards may flood, restricting vehicle movement.
  • Entrances and walkways may become unsafe for staff and visitors.
  • Water may enter buildings, damaging floors, walls or plant rooms.
  • Operations may need to pause while the issue is resolved.
  • Insurance claims may be delayed if maintenance records are insufficient.

For businesses that rely on footfall, scheduled deliveries or 24-hour operations, even short periods of disruption can affect revenue and reputation.

How to assess your site’s surface water drainage risks

A quick visual inspection is often enough to identify early signs of developing problems. Warning signs include:

  • Persistent puddles that remain long after rain has stopped
  • Gullies filling with debris or standing water
  • Silt or residue around drain covers
  • Odours coming from yard drains
  • Water escaping from manholes

For a more detailed assessment, professional drainage contractors can carry out CCTV surveys, jetting and mapping to identify hidden issues such as root ingress, structural defects or collapsed pipework.

Best practice for managing surface water drainage on commercial sites

A proactive approach offers the most reliable protection against flooding and disruption. Effective measures include:

Seasonal gully and channel cleaning

Clearing gullies before and during autumn prevents leaf build-up and blockages.

Regular gutter and downpipe maintenance

Roof drainage is often overlooked but plays a critical role in surface water management.

Routine drain jetting

Jetting removes silt, mud and debris that naturally collects in pipework over time.

Accurate drainage mapping

Knowing where assets are located helps maintenance teams respond more quickly and prevents unnecessary excavation.

Post-storm checks

After periods of heavy rainfall, a quick inspection can identify issues before they escalate.

How Drain & Sewer Services helps businesses manage surface water drainage

Drain & Sewer Services supports commercial sites across the South of England with a full range of services designed to keep surface water systems performing at their best.

This includes:

With more than 50 years of experience, the team understands how to protect sites from flooding, reduce downtime and maintain safe, accessible environments.

Surface water responsibility is essential for safe and reliable site operations

Surface water drainage is often out of sight and out of mind, but when it fails, the consequences can be serious. Understanding responsibility and taking a preventative approach helps reduce the risk of flooding, disruption and costly repairs.

A small amount of regular maintenance can protect your site throughout the winter and ensure drainage systems remain safe and reliable.

Contact Drain & Sewer Services to arrange a drainage inspection or discuss a maintenance plan for your site. Our team can help you keep your site free-flowing and well-prepared for the months ahead.

Frequently asked questions

Who is responsible for surface water drainage on a commercial site?
The property owner is usually responsible for drainage assets within their boundary, including gullies, channels and private pipework. Water companies only manage public sewers.

What causes surface water flooding?
Blocked gullies, heavy rainfall, silt build-up, damaged pipes and inadequate drainage design are the most common causes.

How often should surface water drains be cleaned?
Most commercial sites benefit from seasonal cleaning, especially in autumn and early winter. High-traffic or tree-lined areas may need more frequent maintenance.

Can blocked surface water drains cause internal flooding?
Yes. If water cannot drain away externally, it may find its way into buildings through door thresholds, vents or lower-ground areas.

Do water companies clear private surface water blockages?
No. Blockages on private land must be cleared by the property owner or a professional drainage contractor.