Pipe Size Chart Kenya (2026): Inches to mm for PPR, GI, HDPE and PVC Pipes

Oct 18, 2026

Buy More Mall Kenya

Ask for "half-inch pipe" in one shop and "20 mm" in another and you may be talking about the same thing, or not. Kenyan plumbing mixes inch sizes (from GI steel) with millimetre sizes (for plastic pipes). This chart clears up the confusion so you buy the right pipe and fittings the first time.

Quick answer: For house water supply in Kenya, 20 mm PPR ≈ 1/2", 25 mm ≈ 3/4" and 32 mm ≈ 1". Use 3/4" (25 mm) for the main line from the tank or meter and 1/2" (20 mm) for branches to taps and toilets. Waste pipes are bigger: 1¼"–1½" for basins and sinks, 2" for showers and floor traps, and 4" (110 mm) for toilets and main drains. PPR pipe starts from KSh 170 on Buy More Mall.

Why Inches and Millimetres Do Not Match Exactly

GI (galvanised steel) pipe is named by a nominal inch size that is close to its inside diameter. Plastic pipes such as PPR and HDPE are named by their outside diameter in mm. That is why a 20 mm PPR pipe replaces a 1/2" GI pipe even though 1/2 inch is about 12.7 mm: the walls of plastic pipe are thicker.

Pipe Size Chart: Inches vs mm

Common name	PPR / HDPE (outside mm)	GI nominal (mm)	Typical use in a house
1/2"	20 mm	15 mm	Branches to taps, sinks, showers, toilets
3/4"	25 mm	20 mm	Main line from tank or meter; short runs to several taps
1"	32 mm	25 mm	Main supply to big houses, borehole lines
1¼"	40 mm	32 mm	Rising mains, pump delivery
1½"	50 mm	40 mm	Large supply lines, small institutions
2"	63 mm	50 mm	Bulk supply, irrigation mains

PVC Waste Pipe Sizes

Size	Use
1¼" (about 32 mm)	Wash hand basin waste
1½" (about 40 mm)	Kitchen sink waste
2" (about 50 mm)	Shower, floor trap, washing machine
3"	Branch drains
4" (110 mm)	Toilet and main soil drain
6"	Main drains for blocks and compounds

For waste fittings see PVC waste pipe and drainage fittings prices.

PPR and Waste Pipes on Buy More Mall

PPR Pipes-1/2 – price in Kenya — PPR Pipes-1/2
**KSh 170**

PPR Pipes-3/4 – price in Kenya — PPR Pipes-3/4
**KSh 250**

PPR Pipes-1" – price in Kenya — PPR Pipes-1"
**KSh 350**

PPR Pipe 20Mm (Danco) – price in Kenya — PPR Pipe 20Mm (Danco)
**KSh 380**

PPR Pipe 40Mm – price in Kenya — PPR Pipe 40Mm
**KSh 660**

PPR Pipe 50Mm – price in Kenya — PPR Pipe 50Mm
**KSh 1,200**

PPR Pipe 63Mm – price in Kenya — PPR Pipe 63Mm
**KSh 1,800**

Pvc Waste Pipes 4" Grey – price in Kenya — Pvc Waste Pipes 4" Grey
**KSh 1,100**

Some photos are reference images of the product type, used under open licences. Image credits are on each product page.

Pipe	Size	Price
PPR Pipes-1/2	1/2" (20 mm)	KSh 170
PPR Pipes-3/4	3/4" (25 mm)	KSh 250
PPR Pipes-1"	1" (32 mm)	KSh 350
PPR Pipe 40Mm	40 mm (1¼")	KSh 660
PPR Pipe 50Mm	50 mm (1½")	KSh 1,200
PPR Pipe 63Mm	63 mm (2")	KSh 1,800
Pvc Waste Pipes 4" Grey	4" waste	KSh 1,100

Does Pipe Size Affect Water Pressure?

Pipe size mainly affects flow (how much water arrives) and friction loss over long runs. A pipe that is too small for a long run or for several taps at once gives weak flow even when the tank is high. Pressure itself comes from the height of the tank or from a pump. If taps upstairs are weak, see how to increase water pressure before changing all the pipes.

Rule of thumb: one size bigger for the main line than for the branches, and avoid long 1/2" runs feeding more than two outlets.

Matching Fittings to Pipes

PPR fittings are sized in mm (20, 25, 32…) and fused with a PPR welding machine; see PPR fittings names and sizes.
GI fittings use inch threads; see GI pipe fittings prices.
HDPE uses compression fittings sized by outside mm; see HDPE compression fittings.
Joining PPR to GI or a tap needs a threaded (male or female) adaptor of the right inch size.

Worked Example: Plumbing a Two-Bedroom House

A fundi runs a 25 mm (3/4") PPR main line from the roof tank, then 20 mm (1/2") branches to the kitchen sink, two wash hand basins, a shower and two toilets. The toilets and main drain use 4" PVC, the basins 1¼" waste and the shower a 2" floor trap.

Common Mistakes to Avoid

Asking for "half-inch" without saying PPR, GI or HDPE.
Feeding a whole house through 1/2" pipe.
Using 2" waste for a toilet (it needs 4").
Mixing PPR brands with poor fusion fit.

Not sure which one fits? Send us your details on WhatsApp or through the product page and we will help you choose.

Frequently Asked Questions

What is 20mm pipe in inches?

20 mm PPR or HDPE pipe is the plastic equivalent of a 1/2" pipe.

What size pipe is used for house plumbing in Kenya?

Usually 3/4" (25 mm) for the main line and 1/2" (20 mm) for branches.

What size is a toilet waste pipe?

4" (110 mm) PVC.

Is 25mm the same as 3/4 inch?

Yes, 25 mm plastic pipe is used where 3/4" GI pipe would be used.

Does a bigger pipe increase water pressure?

It improves flow over long runs; pressure itself comes from tank height or a pump.

Prices shown are regular prices on Buy More Mall. Many products are currently on offer, so open the product page to see today's price.

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