# Service charge demand checker: the 18-month rule and the three things every demand must carry > Check a service charge demand against the 18-month rule, the summary of rights and the landlord's address, with what each failure costs and the fix. - Page to cite: https://aeolookup.com/block-management/service-charge-demand-validity-checker/ - Publisher: AEO Lookup (https://aeolookup.com/) - Section: Block and property managers, Service charges and arrears - Published 1 October 2026 - Key fact: Of the four statutory tests, only one is fatal to the money: a cost incurred more than 18 months before the demand, with no written notification in time, is lost under section 20B; the other three make the sum "not due" or withholdable until the demand is re-served correctly. - Sources: Landlord and Tenant Act 1985 ss 20B and 21B; Landlord and Tenant Act 1987 ss 47 and 48; Service Charges (Summary of Rights and Obligations, and Transitional Provision) (England) Regulations 2007; all read on legislation.gov.uk 2026-10-01. Most arrears disputes are not about whether the money is owed. They are about whether the demand was good. A demand that misses one of four statutory requirements gives the leaseholder a lawful reason not to pay, and a tribunal will take that point before it looks at the roof. Run the demand through the checker before it goes out, or before the arrears letter does. **Free tool on the page:** Service charge demand checker: the 18-month rule and the three things a demand must carry. It runs in the browser at https://aeolookup.com/block-management/service-charge-demand-validity-checker/#tool and asks for no sign-up. ## The four tests **Section 20B: the 18-month rule.** A leaseholder is not liable for costs incurred more than 18 months before the demand is served, unless within those 18 months they were notified in writing that the costs had been incurred and that they would later be asked to contribute. This is the one that loses money outright. A late demand with no earlier notification cannot be cured by re-serving it; the cost has gone. The date a cost is "incurred" is normally taken as the date the liability arose, which for most practical purposes is the invoice date. Where there is doubt, use the earlier date and serve the section 20B(2) letter sooner. The letter does not need a figure; it needs to say the cost has been incurred and a contribution will be required. **Section 21B: the summary of rights and obligations.** A demand must be accompanied by the summary prescribed by the 2007 Regulations, in the prescribed form and type size. Without it the leaseholder may withhold the service charge, and any lease provision about late payment, interest included, does not apply while it is withheld. The fix is to re-serve the demand with the summary. Section 21B is prospectively repealed by the Leasehold and Freehold Reform Act 2024, but it remains in force until the replacement provisions are commenced; our guide on [which parts of the 2024 Act are in force](https://aeolookup.com/block-management/leasehold-and-freehold-reform-act-2024-what-is-in-force-managing-agents/) tracks that. **Section 47 of the 1987 Act: the landlord's name and address.** Every written demand must contain the name and address of the landlord, and if that address is outside England and Wales, an address within it for service. The landlord is the freeholder or the RMC, not the agent; a demand on the agent's paper that names only the agent fails. Until the information is given, the service charge is treated as not due. **Section 48 of the 1987 Act: the address for service.** The landlord must by notice give the tenant an address in England and Wales at which notices, including notices in proceedings, may be served. Until it does, rent and service charges are treated as not due. One notice covers every later demand, and most agents print it on the demand itself. ## What the checker does not test Whether the sum is payable at all is a matter for the lease: the service charge year, the on-account machinery, the apportionment and what the landlord may charge for. Whether it is reasonable is section 19. Whether the works behind it were consulted on is section 20, and our [Section 20 checker](https://aeolookup.com/block-management/section-20-consultation-threshold-and-timetable-checker/) covers that. A demand that passes all four tests here can still fail on any of those, and a demand that fails here can be put right in days for three of the four. ## Why the agent should care more than the landlord The money is the client's. The demand is the agent's work product, and a run of defective demands is the most common finding in a management audit when a block changes hands. It is also the easiest thing in block management to get right every time, because the three curable failures are matters of template: the summary attached, the landlord named with its address, the section 48 address printed. Set the template once and the only live question on each demand is the 18-month clock, which our [service charge year calendar](https://aeolookup.com/block-management/service-charge-accounts-when-due-calendar/) tracks from the first cost of the year. ## When the demand is already out and wrong Re-serve. A fresh demand with the summary and the addresses starts the clock for payment again, and the arrears letters should refer to the re-served demand, not the original. Where section 20B has bitten, say so to the client in writing with the figure, because the gap is the client's loss and they will ask why. For the letters that follow a good demand, use the [arrears letter maker](https://aeolookup.com/block-management/service-charge-arrears-letter-template-managing-agents/). This is general information for England, not legal advice. ## Short answers from this page **What is the 18-month rule for service charges?** A cost incurred more than 18 months before it is demanded cannot be recovered, unless within those 18 months the leaseholder was told in writing that the cost had been incurred and that they would be asked to pay. Of the four statutory tests of a demand, this is the only one that loses the money for good; the others make the sum not due until the demand is served correctly. **What makes a service charge demand valid?** It must carry the landlord's name and address, an address in England or Wales for service of notices, the prescribed summary of rights and obligations, and it must be within the 18-month rule. Without the first three the sum is not due, or can be withheld, until the demand is re-served correctly. --- ![](https://aeolookup.com/img/d/owner-line.png) General information for UK small firms, not legal, tax or financial advice.