NATIONAL PLUMBING CODE Philippines · RA 1378
The Revised National Plumbing Code of the Philippines governs all plumbing work in the country. This visual reference breaks down each chapter into clear rules, key dimensions, and illustrated diagrams — making the code readable for master plumbers, architects, civil engineers, and building officials.
Based on the Revised NPC (2000 Edition) under Republic Act No. 1378. Always verify against the official code for permit submissions.
Chapters
Grade ≤75mm
Requirement
Trap Seal
Permit App.
- Permit requirements & who can apply
- Plans signed & sealed by RLMP (6 sets)
- Inspection types & inspector qualifications
- Connection approval — permanent & temporary
- Searchable glossary of all plumbing terms
- Trap, trap arm, trap seal defined
- Drainage, vent & supply system terms
- Fixture unit, branch interval, grade
- Pipe grade: 2% for ≤75mm, 1% for >75mm
- Acceptable fittings for direction changes
- Rodent proofing at pipe penetrations
- Approved pipe materials & standards
- Fixture material & surface requirements
- Clearances: 750mm front, 150mm side (WC)
- Floor drain trap seal & strainer standards
- Minimum fixtures by occupancy — full table
- Cross-connection control & air gap requirements
- Pipe sizing by Water Supply Fixture Units (WSFU)
- PRV required when pressure > 550 kPa
- Hot water max 60°C; shower limit 49°C
- DFU values for every fixture type
- Horizontal branch & stack sizing tables
- Building drain sizing by grade
- Sumps, garage drains & indirect wastes
- Why venting protects trap seals
- Max trap-to-vent distances (Table 7-1)
- Individual, wet, common & circuit vents
- AAV rules & yoke vents for high-rise
- Trap seal depth: 50–100mm required
- Prohibited traps (S-trap, drum, running)
- Cleanout spacing: max 15m horizontal
- Backwater valves for below-grade drainage
- Grease interceptors for commercial kitchens
- Oil & sand interceptors (parking/workshops)
- Clothes washer standpipe: 600–900mm
- AC condensate: indirect waste required
- Tank sizing by DFU load
- Setback distances from structures & wells
- Absorption field design & soil testing
- Dosing chambers & subsurface disposal
- Roof drain sizing by rainfall intensity
- Leaders, conductors & area drains
- Storm & sanitary separation requirement
- Subsoil drainage & sump pumps
- Public-sewer connection & 61m availability rule
- Materials, under-slab & 1.5m/0.6m clearances
- Min 102mm size & 2% slope matrix (Table 12-2)
- Water-pipe trench isolation & abandoned sewers
- Gas/watertight joints & reaming
- Caulked, threaded, wiped, soldered & solvent joints
- Connecting dissimilar materials (adapters/unions)
- Slip/expansion & prohibited joints
- Factory marking & material quality (Table 14-4)
- Copper types & color-stripe codes (K/L/M/DWV)
- Ferrule & bushing tables (14-1, 14-2)
- Closet rings, cleanouts & drainage valves
Why Use This Visual Reference?
The official National Plumbing Code is dense legal text. This site presents each section with clear language, illustrated diagrams, dimension tables, and key requirement callouts — so you spend less time decoding and more time designing.
Important: This reference is for educational purposes. Always cross-check with the official Revised National Plumbing Code of the Philippines (RA 1378, 2000 Edition) and consult a Registered and Licensed Master Plumber for permit submissions and construction decisions.