Hillingdon Council Tax Reduction Overpayment: What Happens and What to Do

How CTR Overpayments Happen

An overpayment — officially called "excess CTR" — occurs when Hillingdon Council discovers that your Council Tax Reduction was calculated on outdated information. The most common triggers are a rise in income that wasn't reported promptly, savings crossing the £6,000 capital limit, or a non-dependant moving into the property without notification.

Hillingdon's scheme requires you to report any change of circumstances within 21 days using the online Change of Circumstances form. If the council finds out about a change after the fact — through a DWP data feed showing your UC award increased, or during a routine review — it recalculates your entitlement from the date the change actually happened, not the date it was reported.

The difference between what you received and what you should have received becomes excess CTR.

How Recovery Works

Unlike Housing Benefit overpayments, excess CTR isn't invoiced separately. Instead, Hillingdon reverses the excess credit on your council tax account. The CTR that was previously applied to your bill is removed for the affected weeks, which increases your outstanding council tax balance.

The council then issues a revised Council Tax Demand Notice spreading the higher balance across your remaining monthly instalments. If the overpayment is large and it's late in the financial year, this can cause a sharp jump in your monthly payments.

There's no separate appeals process for excess CTR recovery — it's treated as a correction to your council tax bill, not a separate debt. However, you can challenge the underlying CTR decision that created the overpayment.

Checking the Calculation

When you receive a revised decision notice, check three things:

The effective date of the change. The council should recalculate from the date your circumstances actually changed, not from an earlier date. If your income rose on 1 June but the council backdates the adjustment to 1 April, that's wrong — challenge it.

The income band assignment. Verify that the council has placed you in the correct band for your new income level. Hillingdon's working-age scheme uses specific thresholds that depend on household size. A family with two children has a Band 3 ceiling of £260 per week — if the council has used the single person thresholds by mistake, your overpayment will be larger than it should be.

Whether the £25 earnings disregard was applied. If the change was an increase in earned income, the £25 weekly disregard should still be subtracted before band assignment. An assessor who forgets the disregard will overstate your assessable income.

If you find an error, request a revision using Hillingdon's Form 147 within one month of the revised decision. The council has two calendar months to respond to an internal revision request.

Preventing Overpayments

The simplest protection is reporting changes quickly. Any increase in income, change in household composition, or rise in savings should be reported within the 21-day window. If you're on a zero-hours contract with fluctuating income, report each significant change rather than waiting for a UC reassessment to trigger an automatic review — UC data feeds can lag behind reality.

Keep dated copies of every Change of Circumstances submission. Hillingdon's portal provides a confirmation screen and reference number. Save both — if the council later claims you didn't report a change, you need proof of the submission date to dispute the overpayment period.

The Hillingdon CTR guide includes a Change of Circumstances Log for tracking exactly this — each change, the date reported, the reference number, and the expected impact on your income band. The guide also walks through Form 147 and the Valuation Tribunal escalation process if the council's recalculation is wrong.

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