Water Companies and the Planning Process: A Developer’s Guide

Water companies and the planning process are closely tied, even though the water company rarely appears on a decision notice. When you develop a site, your regional water and sewerage company is the body that confirms whether the network can take your foul flows and surface water, agrees how you connect, and decides whether it will adopt your new drainage. Get it engaged early and drainage becomes a solved problem. Leave it late and it becomes the reason a scheme stalls. This guide sets out who these companies are, what they control, and how to work with them from pre-application through to adoption.

The term “water authority” is still used loosely, but it now describes today’s privatised water and sewerage companies together with the regulators that oversee them. That whole picture is changing fast in 2026, so the last part of this guide covers the reforms and what they mean for development.

Who are the UK’s water companies (and what happened to “water authorities”)?

Today’s water companies are the regional monopolies that supply water and manage sewerage across England and Wales. The Regional Water Authorities created by the Water Act 1973 were privatised in 1989, forming the water and sewerage companies we deal with now, such as Thames Water, Severn Trent and Southern Water, alongside a handful of smaller water-only suppliers.

Each company holds a licence to act as the statutory water undertaker, sewerage undertaker, or both, for a defined area. You do not choose your provider; the site’s location fixes it. Sitting above them are the regulators: Ofwat for economic regulation and pricing, the Drinking Water Inspectorate for water quality, and the Environment Agency for environmental permitting and flood risk in England. In Wales, Natural Resources Wales covers the environmental role. For how the Environment Agency’s flood role works in planning specifically, see our guide to the Environment Agency’s role in flood risk and planning.

What do water and sewerage companies control?

A water and sewerage company controls three things that matter to a development: the public water supply, the public sewer network (foul, surface water and combined), and the right to connect to or discharge into either. It does not regulate main rivers or set surface water drainage policy; those sit with the Environment Agency and the Lead Local Flood Authority.

That distinction trips up a lot of applicants. The public sewers your drainage might connect to are the water company’s asset, but the way surface water should be managed on the site is judged against national and local drainage policy by the Lead Local Flood Authority. The two run in parallel. If you are unclear on which pipe carries what, and where new connections are allowed, our explainer on foul, surface and combined sewers covers the network types, and the SuDS discharge hierarchy sets out the order in which you have to try each drainage destination before falling back on a sewer.

How do water companies fit into the planning process?

Water companies engage with development at several points, mostly outside the formal application itself. The practical stages are a pre-development enquiry, a network capacity assessment, connection approval, and, where relevant, adoption of new sewers. Handling these in the right order is what keeps drainage off the critical path.

• Pre-development enquiry. Most companies offer a paid pre-development or developer services enquiry that returns asset location plans and an early view on capacity. This is the cheapest way to find out whether the local network can take your flows before layouts are fixed.
• Capacity assessment. The company assesses whether the foul and surface water networks have headroom for your scheme, and whether upgrades are needed. In constrained catchments this is where housing numbers meet infrastructure reality, and where phasing or off-site works can become a condition of proceeding.
• Connection and discharge approval. You have a right to connect foul drainage to a public sewer under section 106 of the Water Industry Act 1991, but the company controls the point and manner of connection and can require conditions. A new surface water connection to a combined sewer is a last resort that needs the company’s agreement, because it adds to overflow pressure.
• Section 104 adoption. Where new sewers are intended to become public, developers enter a section 104 adoption agreement under the same Act, built to the company’s design and construction standards. Many sustainable drainage features are not adopted this way and stay in private or management-company ownership, so agree the maintenance route early.
• Build-over and build-near agreements. If you propose to build over or close to a public sewer, the company must approve the works to protect access to the asset. Discovering an unmapped sewer under a proposed building is a common and expensive surprise, which is why the pre-development enquiry pays for itself.

Are water companies statutory consultees on planning applications?

No. Water and sewerage companies are not statutory consultees on ordinary planning applications in England, with the narrow exception of applications for onshore oil and gas extraction. They are consulted when a council prepares its Local Plan, and local planning authorities can and do consult them informally on major schemes, but there is no general legal duty to consult them on an individual application, or for the council to wait for their response.

This gap is being argued over right now. Through 2025 and into 2026 there were repeated calls in Parliament to make water companies statutory consultees for major housing development, so that infrastructure capacity is tested before permission rather than after. At the same time the government placed a moratorium on creating new statutory consultees while it reviews the whole system, so the position has not yet changed. For developers the takeaway is unchanged either way: do not rely on the planning system to bring the water company to the table. Engage it yourself, early, and put the drainage evidence in your application.

How will water-sector reform change the water company’s role?

The regulatory framework around water companies is being rebuilt, and the direction is toward tighter oversight and stronger infrastructure planning. Two things drive it: a collapse in public confidence after years of sewage discharges, and the Independent Water Commission led by Sir Jon Cunliffe, whose final report in July 2025 made 88 recommendations for reform.

Environment Agency data showed storm overflows in England spilled 450,398 times for a record 3.6 million hours in 2024 — the backdrop to the biggest overhaul of water regulation since privatisation.

The government has confirmed it will abolish Ofwat and fold its functions, together with the water roles of the Environment Agency, Natural England and the Drinking Water Inspectorate, into a single integrated regulator. Ministers described the current set-up as “broken” when they announced the change. The Water (Special Measures) Act 2025, which received Royal Assent in February 2025, has already introduced near real-time monitoring of emergency overflows, restrictions on executive pay, and mandatory pollution incident reduction plans.

The White Paper “A New Vision for Water”, published on 20 January 2026, set out the fuller package, including new regional water system planning authorities (eight in England and one in Wales) intended to line up long-term investment with local growth. A Water Reform Bill is expected to follow. For developers, the practical effect over the next few years is that water infrastructure will carry more weight in where and when growth is allowed. The Thames Water crisis has already shown how capacity limits can hold up approvals, and reform is designed to make that alignment more explicit, not less.

Practical steps for developers

Working well with a water company is mostly about sequence. A few habits keep drainage from becoming the thing that delays permission:

1. Raise a pre-development enquiry early. Get asset plans and a capacity view before you fix the layout, not after.
2. Check for sewers on and near the site. Confirm what crosses the site and whether a build-over agreement is needed.
3. Follow the discharge hierarchy. Evidence that you have tried infiltration and watercourse discharge before proposing a sewer connection; cost alone is not a valid reason to skip a higher option.
4. Settle adoption and maintenance up front. Decide which drainage is offered for section 104 adoption and who maintains the rest.
5. Put the drainage evidence in the application. Because the water company is not a statutory consultee, your submitted surface water drainage strategy has to do the talking.

Frequently asked questions

Talk to Unda about your drainage strategy

Water companies rarely refuse a scheme outright, but a late or weak drainage position can stall one for months. Unda prepares surface water and foul drainage strategies that handle capacity, the discharge hierarchy, connection and adoption, and liaison with your water company and Lead Local Flood Authority, so drainage is evidenced properly at application stage. Start a quote and one of our flood risk and drainage consultants will get back to you within 60 minutes.