Scope of the Code

The code covers:

• Planning and design of water supply systems in buildings
• Requirements for domestic water demand and storage capacity
• Design and installation of plumbing and water distribution systems
• Minimum standards for plumbing fixtures and sanitary fittings
• Drainage and sanitation systems including soil, waste, and vent pipes
• Prevention of backflow and contamination of potable water supply
• Hot water supply systems and related installations
• Wastewater management and disposal systems
• Solid waste management provisions in buildings
• Guidelines for inspection, testing, and maintenance of plumbing systems

The provisions are applicable to:

• Residential buildings and housing complexes
• Commercial buildings such as offices, shopping centers, and hotels
• Institutional buildings including schools and hospitals
• Industrial and mercantile buildings
• Buildings requiring water supply and sanitation systems as part of infrastructure
• New construction projects
• Alterations, additions, or modifications to existing buildings involving plumbing systems

What is NOT Covered

This part of the code does not cover:

• Detailed design standards for specific plumbing components covered under individual Indian Standards (IS codes)
• Municipal water supply system design and large-scale distribution networks
• Industrial wastewater treatment systems specific to manufacturing processes
• Operational procedures for municipal sewerage treatment plants
• Plumbing requirements for ships, aircraft, or specialized transportation systems

Plumbing System Design Philosophy

NBC Part 9 emphasizes:

• Provision of safe and adequate potable water supply for occupants
• Protection of drinking water from contamination and backflow
• Efficient and hygienic drainage and sanitation systems
• Adequate water pressure and distribution throughout the building
• Proper design and installation of plumbing fixtures and fittings
• Safe disposal and treatment of wastewater and sewage
• Integration of water conservation and reuse practices where feasible
• Use of durable materials and proper installation practices to ensure long-term system reliability

The code promotes a comprehensive plumbing design approach that combines safe water supply, efficient sanitation, proper drainage, and environmental protection to maintain public health and sustainable building infrastructure.

General Requirements – NBC 2016 Plumbing Services

Basic Principles of Water Supply Design

The design of a building water supply system should consider several fundamental factors to ensure safe, reliable, and efficient service. These include the number of occupants in the building, minimum water requirements for different uses, water treatment requirements based on water quality, storage capacity, and proper sizing of pipes. Proper planning of these elements ensures that plumbing systems function efficiently and maintain hygienic conditions within buildings.

The principles of water supply, drainage, and sanitation form the foundation of plumbing system design. These principles guide engineers and designers in developing systems that provide adequate water supply, prevent contamination, and safely dispose of wastewater.

Potable Water Supply

All premises intended for human habitation or occupancy must be provided with a safe potable water supply. The water supply should not be connected to unsafe sources and must be protected from backflow contamination to maintain water quality and public health safety.

Water Provision and Pressure Requirements

Plumbing fixtures and equipment should be supplied with adequate water volume and pressure to function properly without causing noise or operational problems. The plumbing system should be designed so that sufficient residual pressure is available at the consumer’s tap, especially at the highest or farthest outlet in the building.

Some plumbing fixtures may require higher pressure levels, and in such cases the system may require pumps, storage tanks, or a combination of both to maintain the required pressure and flow.

Water Efficiency

Plumbing systems should be designed and installed to ensure efficient use of water while maintaining proper performance and hygiene. This includes selecting appropriate fixtures and system layouts that minimize water wastage and promote sustainable water use.

Safety in Plumbing Systems

Plumbing installations should include appropriate safety devices and protective measures to prevent hazards such as contamination, explosion risks, overheating, or system failures. Proper design and installation help maintain safe operation of plumbing systems throughout their service life.

Minimum Water Amenities

Each residential dwelling unit should be provided with essential plumbing fixtures to meet basic sanitation and hygiene requirements. Typically, these include:

• At least one water closet (toilet)
• One lavatory (wash basin)
• A kitchen sink or washing place
• One bathing facility such as a shower or bath

These facilities ensure that minimum standards of sanitation and personal hygiene are maintained in residential buildings.

Drainage System Design

Drainage systems should be designed and installed to prevent blockages, accumulation of solids, and foul conditions. The system must allow adequate access for cleaning and maintenance to ensure long-term reliability.

Proper drainage design also ensures that wastewater and sewage are safely conveyed away from buildings without causing environmental or health hazards.

Plumbing Materials and Workmanship

Plumbing systems should use durable materials and proper workmanship to ensure long service life. Materials should meet relevant standards and installations should be performed in a manner that prevents leakage, seepage, or structural damage to the building.

Fixture Traps and Vent Pipes

Each plumbing fixture connected to a drainage system should include a trap with a water seal to prevent sewer gases, odors, and pests from entering the building. Vent pipes should be installed to ensure proper air circulation in the drainage system and to prevent siphoning of trap seals.

Ventilation of Plumbing Systems

Vent pipes should extend to the open air to allow safe discharge of gases from the drainage system. Proper ventilation reduces the risk of blockages and prevents the return of foul air into occupied spaces.

Testing and Maintenance

Plumbing systems must undergo proper testing and inspection during installation to detect leaks or defects. Regular maintenance is essential to ensure safe operation and long-term performance of plumbing installations.

Additional Plumbing Safety Requirements

The code also emphasizes:

• Preventing substances that may clog or damage pipes from entering drainage systems
• Ensuring adequate lighting and ventilation in areas containing plumbing fixtures
• Providing safe treatment and disposal of sewage where public sewer connections are not available
• Maintaining plumbing systems in a safe and serviceable condition

NBC 2016 Vol 2 Part 9 – Water Supply Requirements for Buildings

Water Supply Requirements

The daily water demand for a building depends primarily on the number of occupants and the type of occupancy. Estimating water demand helps determine the required capacity of water storage tanks, pumps, and distribution systems.

Population estimates are usually based on number of dwelling units or building occupancy type. These estimates form the basis for calculating the required water supply for domestic, sanitary, and other uses.