Published by Verified Plumbers · Last reviewed: April 2026 · Next review: April 2027
Content:
- Quick compliance snapshot
- Who this checklist is for
- 1. Gas Safety Certificate (CP12)
- 2. Legionella risk assessment
- 3. Boiler servicing
- 4. TMV servicing
- 5. Water Regulations 1999 compliance
- 6. Plumbing maintenance obligations
- 7. HMO-specific obligations
- 8. Emergency plumbing obligations
- 9. Documentation — what to keep and for how long
- 10. The compliance cost summary
- Compliance calendar — recommended annual schedule
- Frequently asked questions
- Related guides
- Find a verified plumber for your rental property
- Methodology & sources
Quick compliance snapshot
This table summarises key obligations. Always verify current requirements against the primary sources listed in the methodology section — legislation and guidance change.
| Obligation | Frequency | Legal status | Primary source |
|---|---|---|---|
| Gas Safety check (CP12) | Annual | Legally required | Gas Safety (Installation and Use) Regulations 1998 |
| Gas Safety Record — provide to tenants | Within 28 days of check | Legally required | HSE / Gas Safety Regulations 1998 |
| Legionella risk assessment | On taking control; review on material change | Legally required | HSE ACOP L8 |
| Boiler servicing | Per manufacturer guidance | Best practice — not independently mandated | Gas Safe / manufacturer |
| TMV servicing | Risk-assessment driven | Where risk assessment requires it | HTM 04-01 / risk assessment |
| Water Regulations compliance | All new installations | Legally required | Water Supply (Water Fittings) Regulations 1999 |
| Plumbing maintenance | Ongoing | Legally required | Landlord and Tenant Act 1985 s.11 |
Who this checklist is for
This checklist is for private landlords in London — individual landlords, portfolio landlords and managing agents — who let residential properties containing gas appliances, plumbing systems and hot and cold water supplies.
It covers the plumbing and heating compliance obligations that apply to residential lettings in England. It does not cover electrical compliance, EPC requirements or tenancy law — though all of these interact with plumbing compliance in practice.
If you manage HMOs, section 7 covers the additional obligations that apply.
1. Gas Safety Certificate (CP12)
What it is: The Gas Safety Record — commonly called a CP12, a legacy term from the previous Corgi registration body — is the document issued by a Gas Safe registered engineer after completing the annual safety check of all gas appliances, fittings and flues in the property.
What the law requires:
Under the Gas Safety (Installation and Use) Regulations 1998, landlords must:
- Arrange an annual gas safety check on every gas appliance, fitting and flue they provide
- Use a Gas Safe registered engineer for all gas safety checks
- Provide the Gas Safety Record to existing tenants within 28 days of the check being completed
- Provide the Gas Safety Record to new tenants before they move in
- Keep a record of every gas safety check for a minimum of two years
The 28-day deadline applies to providing the record to existing tenants — not to the engineer issuing the record. New tenants must receive their copy before occupation begins. Source: HSE — Gas safety: landlords FAQ
What the law does not require: A full annual boiler service is not the same as a CP12 safety check — see section 3 for the distinction between the two.
The criminal offence: Failure to comply with the Gas Safety (Installation and Use) Regulations 1998 — including failure to arrange the annual check and failure to provide the record to tenants — is a criminal offence. HSE confirms that landlords can face unlimited fines and up to six months’ imprisonment for serious breaches. Fines in magistrates’ courts are no longer capped — the court sets a level proportionate to the offence and the offender’s means.
The early renewal window: Under the Gas Safety (Installation and Use) (Amendment) Regulations 2018, landlords can arrange the annual check up to two months before the due date and retain the original anniversary date. This allows forward planning without losing the renewal cycle. Source: HSE — Gas safety landlords FAQ
The Renters’ Rights Act 2025 consequence: A missing or defective gas safety position has long been a barrier to serving valid possession notices.
Under the Renters’ Rights Act 2025, Section 21 no-fault evictions are abolished from 1 May 2026. Gas safety compliance remains a critical legal requirement. Non-compliance can lead to enforcement action by HSE or local authorities and may be relied on as evidence of unsafe housing conditions under the Housing Health and Safety Rating System.
Cost (London 2026): Combined gas safety check + CP12: £120–£160
Indicative London 2026 range from the Verified Plumbers directory network. Not a statutory figure. Actual costs vary by property, provider and number of appliances.
2. Legionella risk assessment
What it is: Legionella bacteria can proliferate in hot and cold water systems where water is stored at temperatures between 20°C and 45°C, used infrequently or allowed to stagnate. HSE’s Approved Code of Practice L8 requires landlords to assess and control the risk.
What the law requires:
Under the Health and Safety at Work Act 1974 and the Control of Substances Hazardous to Health Regulations 2002, landlords must:
- Assess the risk of exposure to Legionella from the water system
- Implement appropriate control measures where risk is identified
- Keep records where the level of risk identified makes this appropriate. In simple domestic properties with low risk, HSE confirms that written records are not always legally required for domestic landlords — though keeping a record is strongly recommended as evidence of compliance.
- Review the assessment on taking control of the property, and periodically thereafter — and whenever there is reason to suspect it is no longer valid or there has been a significant change to the water system or occupancy.
The duty is to assess and control the risk — not merely to assess it. Source: HSE — Legionella: what you must do
Can landlords carry out the assessment themselves?
Yes — HSE guidance on Legionella and landlord responsibilities confirms that domestic landlords can carry out their own risk assessment if they are competent to do so. For a simple domestic property with regular water usage and a combi boiler, the risk is generally low and the assessment is straightforward. A professional assessment is advisable where:
- The property has a cold water storage tank in the loft
- The property has multiple occupants with shared hot and cold water systems (HMOs)
- The property is vacant for extended periods — student accommodation in summer, for example
- The water system is complex or has been modified
What HSE does not require: HSE explicitly states that a ‘Legionella test certificate’ is not a legal requirement for domestic residential properties. Testing for Legionella bacteria is not required in most domestic settings — it is a different process from a risk assessment and is generally only required in commercial or high-risk settings. Source: HSE — Legionella and landlords’ responsibilities
London-specific context: Victorian terraces with loft cold water storage tanks — common across inner London boroughs — carry a higher Legionella risk profile than properties with combi boilers. Where a gravity-fed system with a cold water tank is present, a professional assessment and periodic monitoring of water temperatures is good practice.
Cost (London 2026): Professional Legionella risk assessment (residential): £90–£250 Professional assessment (HMO with complex water system): £200–£500+
Indicative ranges. Not statutory figures.
3. Boiler servicing
What the law requires — and what it doesn’t:
There is no independent statutory requirement for annual boiler servicing. However, HSE’s guidance for landlords makes clear that landlords must maintain gas appliances in a safe condition. In practice, annual servicing is the most reliable way to demonstrate that this obligation is being met — and most boiler manufacturers require annual servicing to maintain the warranty.
The distinction matters:
| CP12 Safety Check | Boiler Service | |
|---|---|---|
| Legal status | Legally required annually | Not independently mandated — implied by maintenance duty |
| Purpose | Safety verification of appliances, fittings and flues | Cleaning, efficiency check, component inspection |
| Who performs it | Gas Safe registered engineer | Gas Safe registered engineer |
| Documentation | Gas Safety Record issued | Service record in Benchmark logbook |
| Can be combined | Yes — many landlords book both in one visit, but confirm this explicitly with the engineer | Yes |
The practical reality: A CP12 check takes 30–60 minutes per appliance. A full service takes longer and includes descaling, component inspection and efficiency testing. Booking both in one visit is efficient — but confirm with the engineer in writing that both are being carried out and that the Gas Safety Record will cover all appliances and flues you are responsible for.
Hard water context: In London’s hard water areas, annual servicing is particularly important. Thames Water states water across its region is hard, which can contribute to limescale build-up in boiler heat exchangers over time — annual servicing catches this before it becomes a significant problem.
Cost (London 2026): Boiler service: £100–£130 Combined service + CP12: £120–£160
Indicative ranges. Not statutory figures.
4. TMV servicing
What a TMV is: A thermostatic mixing valve (TMV) blends hot and cold water to deliver water at a safe temperature at the outlet — at a temperature appropriate to the outlet type and risk level, as specified in the applicable scheme or licence condition — preventing scalding.
TMVs blend hot and cold water to reduce scalding risk at outlets. They may be required by project design standards, healthcare guidance such as HTM 04-01, or local HMO licensing conditions — confirm the specific requirement with your borough council’s licensing team. There is no blanket statutory requirement for TMVs in all new-build properties or all HMOs.
What the law requires:
There is no universal statutory requirement for regular TMV servicing. The obligation arises where:
- A risk assessment identifies TMV maintenance as necessary
- The property is subject to HTM 04-01 (healthcare premises) or a similar scheme
- The property is an HMO where licensing conditions specify maintenance requirements
- The TMV manufacturer’s guidance requires servicing intervals
The practical standard: Servicing frequency should follow the applicable scheme, manufacturer guidance, and site risk assessment. Where no scheme applies, follow the manufacturer’s recommended intervals and document the basis for the intervals chosen.
Where a risk assessment identifies TMV maintenance as necessary, follow the assessment’s recommended intervals. Always verify with your borough council’s HMO licensing team for property-specific requirements.
Cost (London 2026): TMV servicing (per valve): £80–£150 TMV standalone service visit (multi-valve property): £250–£300
Indicative ranges. Not statutory figures.
5. Water Regulations 1999 compliance
What the law requires:
The Water Supply (Water Fittings) Regulations 1999 require that all water fittings and plumbing installations in a property are installed and maintained to prevent waste, misuse, undue consumption or contamination of the water supply.
Notifiable work — what must be reported in advance:
Certain types of work must be notified to the water undertaker (Thames Water in London) before work begins, as defined in Schedule 2 of the Regulations. This includes:
- New connections to the water main or communication pipe
- Installation of a reduced pressure zone (RPZ) valve
- Work on water systems in premises used for a purpose listed in Schedule 2 (including commercial premises, food preparation areas and medical facilities)
- Installation of water fittings in certain high-risk fluid category situations
- Any work involving a bath with a capacity greater than 230 litres
For standard residential plumbing work — tap replacement, boiler installation, shower fitting — notification is not required, but all work must comply with the Regulations and be carried out by a competent person.
Backflow protection must be appropriate to the fluid category risk at each point of use. The required level of protection is determined by the fluid category risk — categories 1 through 5 under the Regulations — not the appliance type alone. Source: Water Supply (Water Fittings) Regulations 1999
WaterSafe approved contractors: For new installations, use a plumber familiar with the Water Supply (Water Fittings) Regulations 1999 and able to demonstrate competence in compliance work. WaterSafe is a voluntary industry directory — not a statutory scheme — that lists contractors who have committed to working in accordance with the Regulations.
6. Plumbing maintenance obligations
The legal framework:
Section 11 of the Landlord and Tenant Act 1985 requires landlords to keep in repair and proper working order the installation for the supply of water, gas and electricity, and for sanitation (including basins, sinks, baths and sanitary conveniences).
This is a statutory repairing obligation that cannot be excluded or contracted out of. However, liability for breach depends on the landlord having notice of the defect and being given a reasonable time to carry out repairs. Source: Landlord and Tenant Act 1985, Section 11.
The Homes (Fitness for Human Habitation) Act 2018 reinforces this by allowing tenants to bring civil claims directly in county court where a property contains a hazard affecting fitness for habitation.
What this means in practice:
- Blocked drains, burst pipes, failed boilers and loss of water supply are all maintenance obligations — not optional repairs
- Reasonable response times for non-urgent repairs are expected under the contract of tenancy
- Emergency hazards — including gas leaks, severe water damage and total loss of heating in cold weather with vulnerable occupants — must be addressed promptly
Awaab’s Law — current position for private landlords:
Awaab’s Law came into force for social landlords on 27 October 2025, setting legally enforceable timeframes for addressing serious hazards including damp and mould. GOV.UK confirms that the Renters’ Rights Act 2025 will extend Awaab’s Law to the private rented sector — but implementation timescales are subject to consultation and no date has been confirmed.
Private landlords should treat this as a direction-of-travel signal — not a current statutory obligation — and should monitor GOV.UK for implementation updates.
7. HMO-specific obligations
HMO definition: A House in Multiple Occupation is a property occupied by three or more people forming more than one household who share facilities such as a kitchen or bathroom. Mandatory licensing applies where a property has five or more occupants from more than one household.
Always verify HMO licensing requirements with your borough council’s licensing team — additional licensing schemes vary significantly across London boroughs, and some boroughs require licensing for smaller HMOs than the mandatory threshold.
Additional plumbing obligations in HMOs:
- Legionella risk assessment is more complex in HMOs — shared water systems, multiple shower outlets and higher occupancy all increase risk profile. A professional assessment is strongly recommended.
- TMV installation and servicing is typically required under licensing conditions — confirm with your borough council
- Hot water provision must be adequate for the number of occupants — licensing conditions specify minimum standards
- Cold water storage and hot water cylinder capacity must be sufficient for the property’s occupancy level
London boroughs with additional HMO licensing: Many inner London boroughs — including Hackney, Islington, Southwark, Lambeth, Tower Hamlets, Lewisham and others — operate additional licensing schemes that apply to smaller HMOs. Verify current requirements with your specific borough council before letting any HMO.
See our London Landlord Plumbing Compliance Checklist PDF for the HMO-specific checklist in downloadable format.
8. Emergency plumbing obligations
The legal obligation: Under Section 11 of the Landlord and Tenant Act 1985 and the Homes (Fitness for Human Habitation) Act 2018, landlords must address plumbing emergencies that affect the habitability of the property.
Emergency vs urgent — industry standard guidance:
Note: The response timeframes below reflect industry standard guidance and good practice — they are not currently statutory timeframes for private landlords. Awaab’s Law timescales for private landlords are subject to consultation.
| Situation | Response standard | Legal basis |
|---|---|---|
| Burst pipe with active flooding | Same day — stop damage immediately | Section 11 LTA 1985 |
| Total loss of water supply | Same day | Section 11 LTA 1985 |
| Gas leak | Immediate — Gas Emergency 0800 111 999 | Gas Safety Regulations 1998 |
| Boiler failure — vulnerable occupants, cold weather | Same day | Section 11 / HHFHHA 2018 |
| Sewage backing up into property | Same day | Section 11 LTA 1985 |
| Boiler failure — no vulnerable occupants, mild weather | Within 24–48 hours | Section 11 LTA 1985 |
| Blocked drain — not backing up | Within a reasonable time | Section 11 LTA 1985 |
The emergency plumber relationship: Portfolio landlords managing Victorian terrace stock across inner London boroughs should establish a relationship with a verified emergency plumber before an emergency occurs. An emergency callout to a plumber who does not know the property — where the stopcock is, where the pipes run, what the system configuration is — costs more and takes longer than one who does.
9. Documentation — what to keep and for how long
The retention framework:
| Document | Minimum retention | Recommended retention | Notes |
|---|---|---|---|
| Gas Safety Records (CP12) | 2 years | Duration of ownership | HSE requires 2 years minimum |
| Legionella risk assessments | While current and relevant | Until next assessment | Review and update on material change |
| Boiler service records | Warranty period | Duration of ownership | Evidence of maintenance for insurance |
| TMV service records | Warranty period | Duration of ownership | Required for licensing compliance in HMOs |
| Plumbing repair invoices | 6 years | Duration of ownership + 6 years | Aligned with Limitation Act 1980 limitation period for civil claims |
| Water Regulations notifications | Permanently | Permanently | Evidence of legal compliance |
| Tenant correspondence (repair requests) | 6 years | Duration of tenancy + 6 years | Evidence in dispute resolution |
Why 6 years for invoices and correspondence: The Limitation Act 1980 sets a 6-year limitation period for most civil contract claims. Keeping records for 6 years after the relevant event means you have documentation available if a claim is brought at any point within that window.
Providing records to tenants: Gas Safety Records must be provided to existing tenants within 28 days of the check and to new tenants before they move in. Keep proof of delivery — an email with read receipt or a dated handover note. Source: HSE — Gas safety landlords FAQ
10. The compliance cost summary
All figures are indicative London 2026 ranges from the Verified Plumbers directory network. These are not statutory figures. Actual costs vary by property type, number of appliances, access and provider. Always obtain multiple written quotes.
| Compliance item | Typical London cost 2026 |
|---|---|
| Gas safety check (CP12) | £100–£130 |
| Combined gas safety check + boiler service | £120–£160 |
| Legionella risk assessment (domestic) | £90–£250 |
| Legionella risk assessment (HMO) | £200–£500+ |
| TMV service (per valve) | £80–£150 |
| TMV service (multi-valve property) | £250–£300 |
| Boiler service | £100–£130 |
| Emergency plumber callout | £120–£180 |
| Blocked drain clearance | £120–£180 |
| Burst pipe repair | £260–£320 |
Realistic annual compliance budget for a London rental property: Single-tenanted Victorian terrace with gas heating: £300–£450 per year covering CP12, boiler service and Legionella assessment. HMO with complex water system: £600–£1,200 per year depending on TMV count, Legionella risk profile and emergency callout frequency.
Compliance calendar — recommended annual schedule
This calendar reflects recommended practice — not statutory deadlines. Verify your specific renewal dates against your own records.
| Month | Action |
|---|---|
| January | Review compliance calendar — note all renewal dates for the year |
| February | Book gas safety check if due in March–April |
| March | Carry out annual gas safety check; issue Gas Safety Record to tenants within 28 days |
| April | Review Legionella risk assessment — update if material changes have occurred |
| May | Check boiler service record — book if not completed within last 12 months |
| June | Inspect loft cold water tanks (if present) before summer vacancy periods |
| July–August | Flush water systems in vacant properties — Legionella risk increases with stagnation |
| September | Review TMV service records — schedule if due |
| October | Pre-winter heating check — confirm all radiators heating, system pressure correct |
| November | Insulate outdoor pipes and loft tanks before first frost |
| December | Year-end compliance audit — confirm all records current and filed |
September highlighted: Gas safety check anniversary for properties let from October is due in September. This is the most common renewal month for London lettings — book early to avoid the autumn rush.
Frequently asked questions
Yes — the annual check must cover every gas appliance, fitting and flue that you own and provide for the tenant’s use. This includes the boiler, any gas fires, gas cookers and gas water heaters.
If a tenant has their own gas appliance that you did not provide, you are responsible for the flue and associated pipework but not the appliance itself. Source: HSE — Gas safety landlords FAQ
Yes — HSE guidance confirms that domestic landlords can carry out their own assessment if competent to do so. For a simple domestic property with a combi boiler and regular water usage, the risk is generally low and the assessment is straightforward.
A professional assessment is recommended where the property has a cold water storage tank, multiple occupants sharing hot and cold water systems, or has been vacant for extended periods.
A CP12 is the Gas Safety Record issued after the annual safety check of all gas appliances, fittings and flues. It is legally required annually.
A boiler service is a more thorough inspection involving cleaning, component checks and efficiency testing — it is not independently required by law but is implied by the maintenance obligation and most boiler warranty conditions.
Many landlords book both in one engineer visit — confirm in writing that both are being carried out and that the Gas Safety Record will cover all relevant appliances.
Not yet in the private rented sector. Awaab’s Law came into force for social landlords on 27 October 2025. GOV.UK confirms that the Renters’ Rights Act 2025 will extend equivalent obligations to private landlords — but implementation timescales are subject to consultation and no date has been confirmed.
Monitor GOV.UK for updates.
Certain types of work must be notified to Thames Water in advance under Schedule 2 of the Water Supply (Water Fittings) Regulations 1999. This includes new connections to the water main, installation of RPZ valves, work in commercial premises, and certain high-risk fluid category installations.
Standard residential work — tap replacement, boiler installation, shower fitting — does not require prior notification, but must comply with the Regulations and be carried out by a competent person.
Related guides
- London Plumbing Costs Guide 2026
- Should I Repair or Replace My Boiler?
- London Hard Water Guide — causes, costs and mitigation options
- New Homeowner Plumbing Guide — ten-point check and first six months priorities
- How to Read a Plumbing Quote
Find a verified plumber for your rental property
- Boiler Servicing London — annual service and CP12
- General Plumbing London — maintenance and repairs
- Emergency Plumber London — urgent response
- Blocked Drains London — clearance and CCTV surveys
- Commercial Plumbing London — HMO and portfolio work
Or find your specific borough: All London Boroughs →
Methodology & sources
This checklist is compiled and reviewed annually by the Verified Plumbers editorial team. No payment is accepted from any contractor, compliance service or scheme provider to influence the content of this guide.
Important note: This checklist provides guidance on compliance obligations as understood at the date of review. Legislation and regulatory guidance change — always verify current requirements against the primary sources listed below before making compliance decisions. This guide does not constitute legal advice.
Primary sources:
- Gas Safety (Installation and Use) Regulations 1998
- HSE — Gas safety for landlords
- HSE — Gas safety landlords FAQ
- HSE — Legionella: what you must do
- HSE — Legionella and landlords’ responsibilities
- HSE — Approved Code of Practice L8
- Water Supply (Water Fittings) Regulations 1999
- Water Supply (Water Fittings) Regulations 1999 — Schedule 2
- Landlord and Tenant Act 1985 — Section 11
- Homes (Fitness for Human Habitation) Act 2018
- Limitation Act 1980
- GOV.UK — Renters’ Rights Act 2025 implementation roadmap
- Gas Safe Register — landlord responsibilities
- WaterSafe — approved contractors
- Thames Water — hard water
Pricing methodology: All cost ranges reflect indicative London 2026 figures from the Verified Plumbers directory network. These are not statutory figures. Actual costs vary by property type, number of appliances, access and provider.
Review schedule: This checklist is reviewed every April. Legislation references, cost ranges and regulatory guidance are all verified at each review. The next scheduled review is April 2027.
Reviewed by David, Technical Compliance Editor – Verified Plumbers
This guide is based on publicly available UK legislation and official regulatory guidance. It is intended as general information and does not replace advice from a qualified professional where required.
Last reviewed: April 2026 · Next review: April 2027