uPVC Screen Pipes and Slotted Casing Pipes: How Well Screens Work

A borewell needs two kinds of casing. Plain casing pipe keeps soil and loose rock out of the hole, while a screen pipe, also called a slotted casing pipe, lets groundwater flow in at the water-bearing layer. Getting the screen right is one of the main reasons a well delivers clean water for years instead of pumping sand.

This guide explains what uPVC screen pipes are, how they differ from plain casing, where they sit in a borewell and what to check when you buy them.

What is a screen pipe?

A screen pipe is a length of casing with narrow slots cut through the wall. The slots are sized so that water can pass into the well while most of the surrounding sand and gravel cannot. Screen pipes are joined to plain casing pipes to make one continuous casing string: plain pipe through the upper layers and screen pipe across the aquifer.

Vinyl Pipes supplies screen pipes alongside its uPVC casing pipes. They feature precision-engineered slots that filter sediments to help maintain water clarity.

Where the screen goes in a borewell

In a typical water well the casing string runs from the surface down through the soil and unstable layers. The screen section is placed across the water-bearing formation, and an end cap closes the bottom of the string. The space between the screen and the borehole wall is usually filled with a graded gravel pack, which supports the formation and adds a second filter stage.

• Plain casing runs through the soil and any unstable zones above the aquifer.
• Screen pipe is positioned across the depth where water enters the well.
• Gravel pack fills the space around the screen.
• End cap seals the bottom of the casing string.
• The column pipe and submersible pump hang inside the casing.

Slotted, ribbed and plain: understanding the terms

Buyers search for the same product under several names. Screen pipe, well screen pipe and slotted casing pipe all describe casing with slots for water entry. Ribbed screen pipe is a market term for screen pipes whose wall carries raised ribs. Designs vary between manufacturers, so always ask for the slot size, slot pattern and pipe dimensions rather than relying on the name alone.

Why uPVC works well for screens and casing

Screens sit permanently in groundwater, so the material has to last. Vinyl uPVC casing products are:

• Corrosion and chemical resistant, withstanding pH levels between 2 and 12.
• Smooth inside, which improves flow and resists bacterial growth.
• Lightweight, which makes handling and installation simpler.
• Stiff, with a yield stress of 55 N/mm² to resist deformation under underground pressure.

How to choose a screen pipe

1. Match the slot size to the formation. Slot size is normally chosen from the grain size of the aquifer material and the gravel pack, so that fine particles stay outside the well. Your driller or hydrogeologist can size it from sample analysis.
2. Screen the right depth. Place the screen across the water-bearing zone identified while drilling, not across dry or clay layers.
3. Use the same diameter and joint as the casing so the string stays aligned and sealed.
4. Check the casing grade for the depth. Vinyl offers Deep Well Casing Pipes for greater depths (up to 600 metres) and Medium Well Casing Pipes for moderate depths. See our borewell casing pipe guide.
5. Plan the gravel pack and well development. After installation, the well is developed (pumped or surged) to remove fine material from around the screen.

Frequently asked questions

Is a slotted casing pipe the same as a screen pipe?

Yes. Both terms describe casing pipe with slots that let groundwater into the well. "Well screen" and "screen pipe" are the most common names.

Do I always need a gravel pack around the screen?

A gravel pack is common in sand and gravel aquifers because it holds back fine particles and supports the borehole. The right approach depends on the formation, so follow your driller's recommendation.

Does Vinyl Pipes supply screen pipes?

Yes. Alongside its uPVC Deep Well and Medium Well casing pipes, Vinyl Pipes provides screen pipes with precision-engineered slots. Contact us with your borewell depth and diameter for a quote.

Related reading: pipes for the water well industry and best pipe for submersible pumps.