Why Water and Drainage Are the Real Test of Planning Decisions

Why deferral language around water infrastructure is the clearest signal that a decision is resting on reassurance, not evidence.

Almost every planning application says something about drainage, water, or wastewater recycling. Almost none resolve those issues before the decision is made.

That is not accidental — and it is not a minor technical detail. It is the single clearest indicator of whether a planning decision is being taken on evidence, or on reassurance.

---

Water and drainage are not “details”

Water infrastructure is not cosmetic. It is not optional. It is not a design flourish.

It determines whether:

• foul sewage can be conveyed and treated
• surface water can be safely discharged
• downstream flood risk is increased
• treatment works can cope with additional load
• pollution limits are breached

These are hard system limits, not matters of planning judgement.

Either the capacity exists, or it does not.

---

Why these issues appear on almost every application

Because in most areas:

• wastewater treatment works are already near capacity
• surface water networks are constrained
• receiving watercourses are stressed
• upgrade programmes are unfunded or long-term

This is not a failure of developers to propose green measures. On-site SuDS, attenuation, and “betterment” are usually deliverable.

The problem is network capacity, not site layout.

---

What usually happens instead of resolving the issue

Rather than produce decision-ready evidence, planning reports routinely rely on language such as:

This language sounds technical and controlled. To committee members, it feels like the issue is “in hand”.

In reality, it means something very different.

---

What that language actually means

It means:

• the evidence needed to resolve the issue does not yet exist
• no funded or committed upgrade is in place
• the constraint cannot be removed at this stage
• the problem is being pushed out of the decision window

Procedurally, this is critical.

Planning law does not allow decisions to be taken on evidence that might exist later. It requires evidence to exist at the point of decision.

---

The paradox at committee

Here is the inversion that sits at the heart of the system:

So committees vote yes, not because the issue is resolved, but because it sounds manageable.

The decision feels safe in the room. On the record, it is not.

---

Why water issues are never “resolved later”

Once permission is granted:

• the planning balance is closed
• scrutiny drops to officer level
• refusal becomes practically impossible

the question is no longer “should this be approved?”

It becomes:

“How do we process what was already approved?”

At that stage, drainage and wastewater issues are not re-tested in substance. They are administratively managed, fragmented across conditions, or quietly accepted as unavoidable.

In practice, they are never allowed to change the outcome.

---

Why proper evidence is avoided

Even basic water and drainage evidence would often show:

• no available treatment capacity
• no funded upgrade
• no delivery timescale
• no certainty of improvement

Once that is written down, the decision collapses.

So the system adapts:

• not by fixing the problem
• but by avoiding evidence that would force an honest choice

Deferral is not a temporary step. It is the end state.

---

The obvious solution — and why it never appears

The solution is not complex:

• identify the required upgrades
• cost them properly
• fund them strategically
• deliver them before growth

Often this would require joint action between:

• councils
• water companies
• pooled funding mechanisms

Everyone knows this.

But acknowledging it publicly would mean admitting that:

• current approvals are undeliverable without investment
• housing trajectories are constrained
• some decisions should not yet be taken

So instead, approvals proceed on expectation rather than proof.

---

The simple test that exposes the problem

For water, drainage, and wastewater, there is one decisive question:

If the answer is no, the decision rests on reassurance, not evidence.

No amount of later conditioning can fix that.

---

Why this matters

Water infrastructure does not bend to optimism. It does not respond to wording. And it does not improve because permission was granted.

If the system cannot be honest about water, it cannot be honest about anything.

That is why water, drainage, and wastewater recycling are the clearest place to see whether planning decisions are being made properly — or merely allowed to proceed.

---