PPR Pipe Sizes (20/25/32/40/63 mm): Which Size for Each Line in a Villa

Short answer: PPR pipes are sold by outer diameter: 20 mm for a tap or mixer branch, 25 mm for a bathroom or kitchen branch and manifold outlets, 32 mm for the water heater or floor line, 40-50 mm for the riser, and 63 mm for the villa inlet or manifold header. The table below matches each size to its line and estimated flow.

Which pipe size suits each line in a villa?

The table is a guide for villas and small buildings. The flow figures are calculated at a water velocity of 1.5 m/s in a PN20 pipe (method below), not measured from the catalogue. The final call belongs to the design engineer or licensed plumber, based on fixture count and network pressure.

Outer diameter (mm)	Approx. inch size	Line in the villa	Estimated flow (L/min)
20	1/2"	Branch to a tap, mixer or bidet spray	12
25	3/4"	Bathroom or kitchen branch; manifold outlet	19
32	1"	Water heater line, floor line, small manifold inlet	32
40	1 1/4"	Riser serving several bathrooms	50
50	1 1/2"	Main riser or inlet of a medium villa	79
63	2"	Main inlet or manifold header for several lines	125

How was the flow in the table calculated, and can I rely on it?

Flow = inner cross-section area x water velocity. Inner diameter = outer diameter - 2 x wall thickness. Typical PN20 wall thicknesses from standard manufacturer dimensions: 3.4 mm for 20, 4.2 for 25, 5.4 for 32, 6.7 for 40, 8.3 for 50, and 10.5 for 63. At 1.5 m/s these give the figures above. They are for comparing sizes with each other, not for designing the network: fitting losses, run length, supply pressure and the number of fixtures running at once all change the result. Confirm the real wall thickness from the manufacturer's datasheet before any calculation.

Why does a villa need more than one pipe size?

Because water branches: each branch carries part of the total flow, so sizes step down as you move away from the inlet. The usual villa pattern:

• Villa inlet and distribution header: 50 to 63 mm.
• Floor riser or water heater line: 32 to 40 mm.
• Bathroom or kitchen branch: 25 mm.
• Final connection to the fixture: 20 mm.

Stepping down gradually keeps velocity and pressure right in every branch. Using 20 mm for a line that feeds two bathrooms weakens pressure when both are in use. With a manifold system each outlet is usually 25 mm or 20 mm and the inlet 63 or 32 mm; a later article in this cluster compares the two approaches.

What pipe size should I use for the water heater and hot water line?

Usually 25 or 32 mm depending on heater capacity and the number of outlets. For hot water choose a high pressure class (PN20 or above), because a pipe's pressure rating drops as temperature rises. Check the manufacturer's table for your operating temperature and keep pipes out of direct sunlight by covering or burying them. A later article compares PN10, PN16, PN20 and PN25 in detail. For general rules see how to choose plumbing pipes. Official installation requirements are set by the applicable Saudi plumbing code, which you should consult at design stage.

How much does a PPR pipe cost for each size in Almadah's catalogue?

The pipes are in the Thermal Pipes branch under PPR Supply Pipes & Fittings. Prices are for Al-Zamil PP-R PN20 pipe, 5.8 m long, including 15% VAT, as of 25/10/2026:

Size (mm)	Price per 5.8 m pipe (SAR)
20	29.50
25	47.53
32	77.84
63	335.95

Check the 40 mm and 50 mm prices directly on the product page. Other lines are cheaper, such as the Neproplast thermal pipe, 5.8 m: 25 mm at SAR 32.33 and 32 mm at SAR 50.47. Read the pressure class on each product page before comparing prices; the cheaper pipe is not necessarily the same grade.

Price range of 5.8 m PPR pipes from 20 to 63 mm in the catalogue (VAT-inclusive, 25/10/2026):

• Lowest: SAR 29.50 (20 mm)
• Median price: SAR 64.16
• Highest: SAR 335.95 (63 mm)

Price climbs steeply with size because the plastic in the pipe grows with diameter and wall thickness. These are reference figures, not a price commitment; the actual price depends on supplier, date and quantity.

What sells most in this category?

The order history in this category is still very small. The only item with recorded sales is the PPR thermal manifold 63x32 mm, insulated, 7 lines (5 units, at SAR 1,086.75 including VAT as of 25/10/2026). It is an early indicator, not a market survey. For large quantities you can request a quote.

FAQ

What PPR pipe size feeds a bathroom in a villa?

25 mm for the full bathroom branch, and 20 mm for the final connection to the tap, mixer or bidet spray.

Is 20 mm enough to supply a villa?

No. 20 mm suits a single fixture branch at an estimated 12 L/min. The inlet and risers need 32 to 63 mm depending on the number of fixtures.

What size pipe should go to the water heater?

Usually 25 or 32 mm depending on heater capacity and outlets, in PN20 or higher for hot water.

What is the difference between millimetre and inch sizes for PPR pipe?

The millimetre size is the outer diameter: 20 mm is about 1/2", 25 mm about 3/4", 32 mm about 1", and 63 mm about 2".

How much is a 32 mm PPR pipe?

As of 25/10/2026, VAT-inclusive: SAR 77.84 for an Al-Zamil PN20 pipe, 5.8 m, and SAR 50.47 for a Neproplast thermal pipe of the same length.

Is the flow in the table real?

It is a calculated estimate at 1.5 m/s for comparing sizes, not a network design. The designer accounts for losses, pressure and simultaneous fixtures.

Related articles

• Guide to PPR supply pipes, valves and fittings: sizes, pressures and welding
• How to choose plumbing pipes
• Thermal Pipes
• Fittings and Elbows
• Arabic version: مقاسات مواسير PPR (independent Arabic article)