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Plumbing pipes — CPVC, UPVC, PPR, GI and copper explained

Plumbing is invisible once walls are plastered — making the right material choice critical. A wrong choice means breaking walls for repairs decades later.

Simple summary — for homeowners

For new residential construction in Bengaluru, CPVC is the standard choice for hot and cold water supply inside the home — it handles high temperatures, has a 50+ year lifespan and is easy to work with. PPR is a premium alternative with heat-fused joints that are completely leak-proof. Never use GI pipes for concealed plumbing — they rust and require replacement within 15–20 years. For drainage and sewage, UPVC or CI pipes are the right choice. Always use IS-marked pipes from reputed manufacturers.

Pipe types comparison

Type
Full name
Max temp
Life
Corrosion
Best use
CPVC
Chlorinated Polyvinyl Chloride
Up to 93°C
50+ years
Excellent
Hot and cold water supply inside home
UPVC
Unplasticized Polyvinyl Chloride
Up to 60°C
50+ years
Excellent
Cold water supply, drainage
PPR
Polypropylene Random Copolymer
Up to 95°C
50+ years
Excellent
Hot and cold water, concealed plumbing
GI
Galvanized Iron
Up to 120°C
15–25 years
Poor — rusts over time
Older buildings, gas lines
CI
Cast Iron
Up to 120°C
50+ years
Fair
Underground drainage, soil pipes
HDPE
High Density Polyethylene
Up to 60°C
50+ years
Excellent
Underground water mains, borewell
Copper
Copper pipe
Up to 120°C
70+ years
Excellent
Premium plumbing, gas lines

CPVC vs PPR — the key choice for supply lines

CPVC
Solvent-welded joints — chemical bonding
Easier to work with — more available fittings
Handles hot water up to 93°C
IS 15778 certified products widely available
Lighter than PPR — easier to handle
Standard choice for most residential projects
PPR (Polypropylene Random)
Heat-fused joints — completely leak-proof
No chemicals needed — safer joints
Handles hot water up to 95°C
Higher pressure rating than CPVC
Food-safe — no chemical leaching
Premium choice — higher material cost

Essential fittings

Fitting
Purpose
Location
Ball valve
Isolation — on/off control for individual fixtures
Every fixture, main supply
Gate valve
Full bore isolation — minimum flow restriction
Main supply line, tank inlet
Check valve
Prevents backflow — one direction only
Pump outlet, tank inlet
Pressure reducing valve (PRV)
Reduces inlet pressure to safe level
Building inlet — mandatory above 3 bar
Float valve
Automatically stops filling when tank is full
Overhead tank, sump
Flush valve
Controls WC flushing
WC cistern

Plumbing design principles

01
Separate hot and cold lines
Hot water lines must be insulated and run separately from cold water lines. Crossing or bundling hot and cold pipes causes energy loss and condensation issues.
02
Minimum slope for drainage
All drainage pipes must slope minimum 1:80 (1.25%) towards the drain. Insufficient slope causes slow drainage and blockages. Soil pipes (WC) need minimum 1:40 slope.
03
Provide access panels
Every concealed valve must be accessible through an access panel. This is non-negotiable — no valve should be permanently buried in a wall.
04
Pressure test before closing walls
All supply lines must be pressure-tested at 1.5× working pressure for minimum 2 hours before walls are plastered. Any drop in pressure indicates a leak.
05
Use IS-marked pipes only
Always specify IS 15778 for CPVC, IS 4985 for UPVC. IS marking ensures the pipe meets minimum wall thickness and pressure ratings. Never compromise on this.
Homekrate recommendation
Basic
CPVC for supply + UPVC for drainage
IS-marked pipes. Reliable 50+ year system for standard residential projects.
Standard
CPVC for supply + UPVC for drainage + CI for soil pipes
Our default. Cast iron soil pipes reduce noise transmission significantly.
Premium
PPR for supply + UPVC for drainage + CI for soil pipes
Heat-fused PPR joints eliminate leak risk. Best long-term performance.
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