Pump Strainers & Filters

Pump strainers and filters are inline fluid-handling components that capture debris, sediment and particulates before they reach a pump, valve or downstream equipment. In water, plumbing, irrigation and industrial process systems, they are the first line of protection against blockages, impeller wear and premature seal failure, keeping flow rates steady and maintenance intervals predictable. At RS New Zealand, we stock a broad range of pump strainers and filters, including Y-strainers, basket strainers, inline pump filters and stainless steel water strainers, sized for domestic plumbing runs through to industrial process lines across New Zealand.

How Pump Strainers and Filters Work

A pump strainer or filter sits upstream of the equipment it protects, passing fluid through a mesh screen, cartridge or filter element that traps solids while letting the liquid through. Coarser debris, such as leaves, grit, scale flakes and pipe swarf, is caught by strainers, typically fitted with a stainless steel mesh sized in millimetres. Finer sediment, rust particles and process contaminants are handled by pump filters, which use tighter media rated in microns. In both cases, the captured material is removed at scheduled service intervals, either by lifting a basket, unscrewing a Y-strainer plug, or replacing a cartridge. The result is protection for pump internals, valves and instrumentation, with flow rate and pressure held within spec across the service life of the system.

Types of Pump Strainers and Filters

The types below cover the strainer and filter formats most commonly specified for water, plumbing and industrial applications in New Zealand.

Inline Pump Filters

Inline pump filters are cartridge-based units plumbed directly into the pipe run, sized to trap sediment down to a specified micron rating. They suit clean-water applications, booster systems and process lines where fine particulate control matters, and the cartridge is replaced rather than cleaned.

Y-Strainers

Y-strainers take their name from the angled leg that holds the mesh screen. They are compact, cost-effective and suit horizontal and vertical pipe runs in water, steam and low-viscosity fluid systems. The screen can be removed for cleaning by unscrewing the blowdown plug or the strainer cap.

Basket Strainers

Basket strainers use a larger cylindrical basket to catch heavier debris loads at high flow rates, making them the preferred choice for pump-suction protection on industrial and commercial water systems. The larger basket volume means longer intervals between clean-outs on debris-heavy lines.

Water Pump Strainers

Water pump strainers protect submersible and inline water pumps used in irrigation, rainwater harvesting and general water transfer. They combine a coarse intake screen with a housing sized to the pump's flow rate, keeping impellers clear of leaves and grit.

Stainless Steel Water Strainers

Stainless steel water strainers use a corrosion-resistant body and mesh, suiting potable water, marine, dairy and outdoor applications where longevity and hygiene are priorities. The mesh is available in a range of aperture sizes for coarse or fine filtration.

How to Choose the Right Pump Strainer or Filter

Work through the criteria below to match a strainer or filter to your system.

• Fluid Compatibility: Match the strainer or filter body and seal materials to the fluid being handled, including any chemicals, temperature range and cleaning agents used.
• Mesh Size or Filtration Level: Coarse mesh (measured in mm) suits pump protection from debris while fine media (measured in microns) suits sediment and particulate removal downstream. Our guide to [understanding filtration and mesh ratings for pump protection] covers how to choose the right specification for typical NZ applications.
• Flow Rate: Confirm the unit is sized for the system's flow rate at working pressure, since undersized strainers cause pressure drop and premature clogging. A flow meter fitted upstream is the most reliable way to establish actual flow rate before you specify.
• Pipe Connection Size: Match the inlet and outlet to the pipe run, either BSP threaded or flanged, in the correct DN or nominal bore.
• Material: Choose plastic for cost-driven potable water use, brass for general plumbing, and stainless steel for corrosive, high-temperature or hygienic applications.
• Pressure and Temperature Ratings: Confirm the unit's PN rating and maximum working temperature meet the system's design conditions. Fittingpressure sensors either side of the strainer is the standard way to detect a rising pressure drop as debris accumulates, so servicing happens before the strainer clogs.
• Indoor or Outdoor Use: Outdoor and buried installations need corrosion-resistant materials and UV-stable housings where exposed.

Applications of Pump Strainers and Filters

Pump strainers and filters are used across a wide range of water and process systems in New Zealand, including:

• Water Supply Systems: Municipal and building supply lines carry grit and rust that strainers keep clear of meters, valves and appliance fittings.
• Irrigation Systems: Pump filters capture sediment from bore, rainwater and channel supply before it reaches sprinklers, drip lines and delivery pumps.
• Pumps and Booster Systems: Suction-side strainers keep debris clear of impellers and mechanical seals, extending pump life and steadying pressure.
• Industrial Process Equipment: Fine cartridge filtration protects instrumentation, control valves and heat exchangers from process contamination.
• HVAC Systems: Chilled-water and heating circuits carry scale and biofilm that strainers keep clear of pumps, coils and control valves.
• Agricultural Water Systems: Dairy shed washdown, stock water and horticultural spray lines rely on inline filtration to protect nozzles, valves and delivery pumps.
• Commercial Plumbing Installations: Backflow preventers, thermostatic mixing valves and pressure-reducing stations perform better with a strainer upstream.

In each case, the strainer or filter safeguards the downstream pump, valves and instrumentation, protecting equipment investment and stabilising performance.

Your Trusted Supplier & Distributor of Pump Strainers & Filters

RS New Zealand is a trusted supplier and distributor of pump strainers and filters at competitive prices, stocking Y-strainers, basket strainers, inline pump filters, water pump strainers and stainless steel water strainers from reliable partners including Xylem Flojet, Parker and our own RS PRO range. Beyond pump strainers, we also stock water pumps and valves and fittings to pair with your strainer or filter to create a full system.

Ordering from RS online is simple: filter by connection size, mesh rating, material and pressure rating, review the datasheet, then add to cart for quick checkout. For full details on delivery services and fees for NZ orders, please refer to our Delivery page.