Tenant vs. Landlord: Who Is Responsible for Unvented Cylinder Safety?

Unvented hot water cylinders are great for strong, mains-pressure showers. However, they’re also pressurised systems. That’s why the UK’s Building Regulations treat them differently from a traditional vented cylinder.

If you’re a property manager/landlord, or a tenant trying to work out “who’s responsible”, it helps to separate two things:

1. Legal compliance and safe installation (G3/Part G)
2. Ongoing safety checks, servicing, and repairs once the tenant moves in

What the G3 Building Regulations Actually Cover

Unvented hot water storage systems fall under Building Regulations Part G (section G3), which exists because a poorly installed system can be dangerous. It also states that a hot water storage system without a vent pipe “may only be installed by a person competent to do so”, with precautions to prevent overheating and to make sure any discharge from safety devices is conveyed safely and visibly.

Approved Document G reinforces the point for “building owner/occupiers”: the safety and performance of an unvented system depends on correct installation, and owners/occupiers should choose installers with the necessary skills (for example, via a competent person scheme).

In other words, tenants and owners shouldn’t be touching unvented safety controls. Installation and safety-critical work is for properly qualified (G3) engineers.

Who’s Responsible in a Rented Property?

In a rented property, responsibility is divided between tenants and owners.

Landlord/Property Manager Responsibilities

In England and Wales, landlords have a legal duty under Section 11 of the Landlord and Tenant Act 1985 to keep in repair and proper working order the installations for space heating and heating water.

In other words, if the unvented cylinder is part of the property’s hot water system, the landlord is usually responsible for keeping it working and safe.

That usually includes:

• Arranging repairs when faults are reported
• Maintaining safety-critical parts
• Keeping service records and certificates for the property file

Tenant Responsibilities

Tenants aren’t expected to service an unvented cylinder. Their responsibilities are usually related to use and reporting, like:

• Reporting leaks, loss of hot water, noises, or water running through the tundish
• Not tampering with valves, caps, discharge pipework, or control settings
• Allowing reasonable access for inspection/repairs (per the tenancy agreement)

If a tenant causes damage (for example, by interfering with safety devices), that’s where costs can become a tenancy/insurance issue.

The Annual Safety Check

There isn’t a single, universal “annual certificate” law for unvented cylinders in the same way as gas appliances have a Gas Safety Certificate. However, for landlords and property managers, treating an annual safety check as optional is risky.

• The Hot Water Association’s consumer servicing guide sets out service checks that should be carried out every 12 months, and says continued 12-monthly servicing is recommended (and, in most cases, that is a condition of the manufacturer’s warranty), carried out by a competent service engineer.
• Manufacturer instructions often make maintenance explicit. For example, a Kingspan requires an annual service for safety and operation, with checks performed annually by a competent installer. The guarantee may be void without proof of annual servicing.

Landlords have a legal duty to keep the hot water installation safe and working, and annual servicing is one of the clearest ways to show that you’ve met that duty.

Who Does What?

• Landlord/PM:
  • Book an annual unvented cylinder safety service
  • Keep the Benchmark/service record updated
  • File the certificate
  • Respond quickly to any reported discharge or leaks
• Tenant:
  • Report issues early (especially any dripping at the tundish)
  • Don’t alter safety components
  • Provide access for the engineer

Let the Experts Help

EasyFlow provides annual servicing and maintenance for unvented cylinders, and our annual service includes testing safety valves, recharging pressure vessels, cleaning the pressure reduction valve, and issuing a service certificate. If you’d rather wrap everything into a single cost, we also offer a maintenance plan that includes an annual service plus call-outs, parts, and labour for repairs. Contact us for more information.