Approved Document G Frequently Asked Questions – Sanitation and Water Efficiency
This official guidance, issued by the Department for Communities and Local Government (now the Department for Levelling Up, Housing and Communities), provides clarifications on Part G of Schedule 1 to the Building Regulations. This version of the frequently asked questions was published in March 2016 to support the 2015 edition of Approved Document G including the 2016 amendments. It serves as a secondary reference for interpreting statutory requirements across England regarding sanitation, hot water safety, and water efficiency.
The document covers a broad regulatory scope, including Requirement G1 (Cold Water Supply), Requirement G2 (Water Efficiency), Requirement G3 (Hot Water Supply and Systems), and Requirements G4 through G6 covering sanitary conveniences, bathrooms, and food preparation areas. It defines technical standards for wholesome water, softened wholesome water, and water efficiency targets. The guidance provides specific details on building types subject to these regulations, including new dwellings, buildings created by a change of use, and workplace environments.
Professional users can find specific interpretations of section numbers such as Paragraph 3.60 regarding discharge pipes and Paragraph 3.11 concerning storage vessel standards. The text also clarifies the application of the Water Calculator methodology and the mandatory temperature limits for hot water delivery in residential settings.
Cold Water Supply and Softened Water
Requirement G1 dictates that wholesome water must be provided to any location where drinking water is drawn and any sink located in food preparation areas. The regulations also permit the use of alternative water sources for certain functions.
- Wholesome or Softened Wholesome Water: Must be supplied to washbasins or bidets adjacent to sanitary conveniences, and to baths or showers in bathrooms.
- Alternative Sources: Greywater and rainwater may be supplied to sanitary conveniences fitted with a flushing device under G1(2).
- Softened Wholesome Water: Introduced to address areas with extremely hard water where softening processes might result in sodium levels exceeding standard wholesome water limits.
- Kitchen Sinks: While softened water is permissible if it remains wholesome, it is preferable for the cold supply to the kitchen sink to come directly from the mains to minimize risks from inadequate maintenance.
Water Efficiency Targets and Monitoring
Requirement G2 and Regulations 36 and 37 introduce minimum water efficiency standards for new homes, including those created through a change of use. Compliance is measured by estimated average daily usage per person.
- Standard Threshold: Average water usage must not exceed 125 litres per person per day.
- Planning Condition Threshold: A tighter limit of 110 litres per person per day applies if specified by planning permission.
- Water Calculator: Estimated usage must be calculated using the methodology in Appendix A of Approved Document G, unless 'deemed to satisfy' fittings are utilized.
- Notification: A notice stating potential consumption must be given to the building control body within five days of work completion.
Hot Water Supply and Safety Systems
Requirement G3 extends safety regulations to all types of hot water systems, not just unvented ones, and introduces mandatory temperature controls for baths in new dwellings.
- Temperature Limits: Hot water supplied to a bath in a new home must be limited to no more than 48°C, typically achieved via a thermostatic mixing valve (TMV).
- Small Water Heaters: Systems with a capacity of less than 15 litres are subject to the regulations but are generally not notifiable to building control unless they involve notifiable electrical work under Part P.
- Combi Boilers: Must be notified regardless of storage capacity as they are combustion appliances and form part of a fixed building service.
- Discharge Pipes: While the Approved Document suggests polybutalene or cross-linked polyethylene, polypropylene to BS EN 1451-1 is acceptable if it resists the temperature of the water discharged.
Sanitary Conveniences and Food Preparation Areas
Requirements G4, G5, and G6 outline the provisions for toilets, bathrooms, and kitchens. These rules ensure hygiene by separating sanitary facilities from areas where food is handled.
- G4 Separation: In dwellings, a toilet must be separated from a food preparation area by a door; a ventilated lobby is not required.
- Workplace Requirements: Under the Workplace (Health, Safety and Welfare) Regulations 1992, toilets in workplaces must not open directly into rooms where food is handled, often necessitating a ventilated lobby.
- G5 Bathroom Provision: Dwellings and residential buildings (such as hostels) must provide a bathroom with a washbasin and either a fixed bath or shower.
- G6 Kitchen Sinks: A suitable sink must be provided in every area where food is prepared.
Frequently Asked Questions
When must the Water Calculator be completed?
It should be completed during the design stage when fittings are specified and revised if they change; a notice of potential consumption must be submitted to the building control body within five days of work completion.
Is a thermostatic mixing valve required when installing a new bath in an existing dwelling?
No, the 48°C temperature limit applies only to baths in new homes or those created by a change of use, though fitting a TMV in existing homes is considered good practice for safety.
Can polypropylene discharge pipes be used for safety relief?
Yes, polypropylene pipes to BS EN 1451-1 are acceptable provided they can safely resist the temperature of the discharged water and comply with sub-paragraphs a, b, and d of Paragraph 3.60.
What are the water efficiency targets for new dwellings?
The standard requirement is 125 litres per person per day, which can be reduced to 110 litres per person per day if required by a planning permission condition.
Is a ventilated lobby required between a toilet and a kitchen in a house?
No, Requirement G4 only requires that the toilet be separated by a door from the food preparation area in a dwelling.
Do vitreous enameled carbon steel storage vessels comply with Part G?
Yes, if they are fitted with suitable safety devices and have passed a relevant pressure test, such as BS EN 89:2000, they should be accepted by building control.
Are overheat cut-outs required for indirectly heated vented systems?
Yes, an overheat cut-out must be incorporated for all indirect heat sources to disconnect heat supply if the stored water overheats, though these may be self-resetting.
Which version of Approved Document G applies to projects started after February 2016?
Projects starting after 15 February 2016 must follow Volume 1 of the 2015 edition with the 2016 amendments.
