What a house actually costs to run (the number nobody budgets)

This one's for first-time buyers, new landlords and anyone whose budget spreadsheet has one line on it that says "mortgage". The monthly payment your broker quotes you is usually only 60 to 70% of what the house actually costs to run. Here's the full stack, with current sourced figures, and how to check them for a specific property before you offer.

The mortgage is the headline, not the bill

Lenders stress-test whether you can afford the mortgage. Nobody stress-tests whether you can afford the house. Those are different questions. The gap between them is why people end up "house-poor": technically homeowners, practically skint.

Everything below sits on top of the mortgage, every month, forever.

Council tax: £100 to £300+ a month

Every home in England and Wales sits in a band from A to H, set by the Valuation Office Agency. The average Band D bill in England for 2026 to 27 is £2,392 a year, about £199 a month, up 4.9% on last year. Your actual bill depends on the band and the council, so the range is wide: a Band A in a cheap authority might be ~£1,300 a year; a Band G in an expensive one can clear £4,000.

The catch: the band follows the property, not the price you paid. Check it before you offer at gov.uk/council-tax-bands (Scotland: the Scottish Assessors website). Takes 30 seconds. Do it for every property you view.

Energy: the price cap is a rate, not a ceiling

The Ofgem price cap for 1 July to 30 September 2026 works out at £1,663 a year for a typical dual-fuel household paying by direct debit, roughly £139 a month. Unit prices rose 13% this quarter; the headline figure barely moved only because Ofgem simultaneously cut its definition of "typical" use (households now use about 7% less electricity and 17% less gas than the old assumption). Two things people get wrong:

1. The cap limits the unit price (currently 26.11p/kWh electricity, 7.33p/kWh gas, plus standing charges), not your total bill. A big, draughty house blows straight past the "typical" figure.
2. The cap resets every three months. Budget for movement.

Check the property's EPC free at gov.uk/find-energy-certificate (England, Wales, NI; Scotland has its own register). It estimates the property's actual energy costs and lists what it'd cost to improve. An EPC of D or worse on a 1930s semi is a very different bill from a C on a new-build.

Water: ~£53 a month and rising

The average combined water and sewerage bill in England and Wales for 2026 to 27 is £639 a year (Water UK), up £33 on last year, and that follows a £123 jump the year before as the industry's investment programme kicked in. It varies heavily by region (South West Water averages around £743). Metered properties: ask the seller for a recent bill.

Insurance: ~£31 a month, and buildings cover isn't optional

The average combined buildings and contents policy was £375 a year in Q1 2026 (ABI premium tracker). Buildings-only averaged £306, contents-only £117 over the same quarter. If you have a mortgage, the lender will require buildings insurance as a condition. It's not a nice-to-have. Flood risk, subsidence history and non-standard construction can multiply these numbers, which is another thing to research before offering, not after.

Broadband: ~£26 to 30 a month

Ofcom put the average UK broadband spend at £26 a month (January 2025 data), with out-of-contract customers paying £7 to 9 more. Small line item, but it's there every month, and most providers now bake in annual mid-contract price rises of £3 to 4.

Leasehold? Add service charge and possibly ground rent

If you're buying a flat, this is the line that hurts. Hamptons' service charge index puts the average annual service charge for a leasehold flat at £2,405 in 2025, over £200 a month, before you've paid for anything inside your own front door. Ground rent is banned on new leases granted since 30 June 2022 (Leasehold Reform (Ground Rent) Act 2022), but pre-2022 leases still pay it. The government announced plans in January 2026 to cap it at £250 a year, but that isn't law yet and may not bite until 2028 at the earliest. Get the last three years of service charge accounts before you offer. Full detail in the freehold vs leasehold guide.

Maintenance: the 1% convention

A common rule of thumb says budget around 1% of the property's value per year for maintenance and repairs. It's a convention, not a law: a new-build might run well under it for a decade, a Victorian terrace can eat it twice over. But 0.5 to 1% a year is a sane planning range, and the point is that the number is not zero, which is what most first-time buyers budget.

Why it's real, the big-ticket lifecycles (typical trade ranges, not quotes):

• Boiler: 10 to 15 year lifespan, £2,000 to £4,500 to replace
• Roof: decades of life, but a full re-cover on a semi is commonly £5,000 to £12,000+
• Windows: roughly £500 to £900 per window for double glazing

None of these are monthly bills. All of them arrive eventually, usually without warning. The 1% fund is how you pay for them without a credit card.

Life insurance and income protection

Not legally required, but most people with a mortgage and dependants take something so the debt doesn't land on a partner or family. Costs vary hugely with age, health and cover, commonly somewhere in the £10 to £40 a month range for straightforward level term cover, but that's indicative only. This is a personal decision; talk to an FCA-authorised adviser, not a guide.

Worked example: a £250,000 semi

Freehold three-bed semi, £250,000, 10% deposit, £225,000 mortgage over 30 years at an illustrative ~4.5%:

The mortgage is about 63% of the real number. If your budget says "I can afford £1,150 a month", you can afford roughly a £155k house, not a £250k one. That's the sentence this whole guide exists for.

How to check all of this before you offer

1. Council tax band: gov.uk/council-tax-bands, free and instant.
2. Energy: pull the EPC at gov.uk/find-energy-certificate, free, and it shows estimated running costs.
3. Bills: ask the seller (via the agent) for recent energy, water and, for leaseholds, service charge statements. Sellers who won't share are telling you something.
4. Insurance: get an indicative quote on the actual postcode before exchange. Flood-risk postcodes surprise people.
5. Survey: a Level 2 or 3 survey flags the boiler, roof and windows before they're your problem, and the surveys guide covers which level to pick.

Mistakes people make

• Budgeting to the mortgage payment. The mortgage is 60 to 70% of the true cost. Leave headroom or the house owns you.
• Ignoring the council tax band until the first bill. £100+ a month of difference between bands, checkable in 30 seconds, and almost nobody checks.
• Treating "typical" energy figures as their figure. The cap headline assumes typical use. A poorly insulated house isn't typical. Read the EPC.
• Buying leasehold without reading the service charge accounts. £200+ a month average, uncapped, and rising faster than inflation.
• Having no maintenance fund. The boiler doesn't care that you just spent your savings on the deposit.
• Landlords forgetting voids. If you're buying to let, every one of these costs runs whether or not rent is coming in, and the yield guide shows how to build them into the sums.

Sources: Ofgem price cap, 1 July to 30 September 2026 · Ofgem press release, July 2026 cap · MHCLG: Council Tax levels set by local authorities in England 2026-27 · GOV.UK: Check your Council Tax band · GOV.UK: Find an energy certificate · Water UK: annual average bill changes 2026-27 · ABI: home insurance premium tracker, Q1 2026 · Ofcom: Pricing and consumer engagement report · Hamptons: 2025 Service Charge Index · GOV.UK: Leasehold Reform (Ground Rent) Act 2022 guidance

Education, not financial advice. For mortgage advice, speak to an FCA-authorised broker.

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