What Size Overflow Rodent & Insect Screen Do I Need for a 1" Outlet?
If you’ve identified that your water tank has a 1-inch overflow outlet, you’re already thinking in the right direction. Protecting that outlet with a properly fitted overflow rodent and insect screen is one of the simplest ways to safeguard your system. But while “1 inch” sounds straightforward, there are a few important details that determine which screen you actually need.
A 1” outlet (approximately 25mm or 28mm depending on specification) is commonly found on domestic cold water storage tanks, rainwater harvesting systems, agricultural tanks, and smaller commercial water storage installations. Because overflow pipes discharge externally, they are often exposed to outdoor conditions, and that makes them a prime entry point for rodents, insects, and debris.
Before choosing a screen, it’s important to understand exactly what type of connection you have.
Step One: Identify Your 1” Outlet Type
Not all 1” outlets are the same. Your pipe could be:
A smooth push-fit pipe end
A compression fitting
A 1” BSP male thread
A 1” BSP female thread
The correct overflow rodent and insect screen depends entirely on this connection type. Measuring accurately and identifying whether your fitting is threaded or smooth will prevent ordering the wrong product.
Option 1: 1” Universal Connector (Smooth Pipe)
If your overflow is a smooth 1” pipe, a universal connector is often the most practical and flexible choice. The 1” Overflow Rodent & Insect Screen with Universal Connectors is specifically designed to fit securely onto 1” outlets while maintaining full water discharge capacity:
Universal connectors are particularly useful for retrofit installations. They accommodate slight pipe variations and create a tight seal without requiring complex modifications. This makes them ideal for domestic upgrades and agricultural applications where pipe tolerances may differ.
Option 2: 28mm / 1” Compression Fitting
If your system uses a compression-style connection, you’ll need a screen designed to mechanically secure around the pipe. The 28mm / 1” Overflow Rodent & Insect Screen (Compression) offers a firm, fixed installation:
https://www.mp-products.co.uk/28mm--1-overflow-rodent-and-insect-screen-compression-4347-p.asp
Compression fittings provide added stability and are ideal where a permanent, secure connection is preferred.
Option 3: BSP Threaded Fittings
If your overflow outlet is threaded, you must match the thread type exactly.
For a 1” BSP Male Thread screen:
https://www.mp-products.co.uk/1-overflow-rodent-and-insect-screen-bsp-male-thread-130-p.asp
For a 1” BSP Female Thread screen:
https://www.mp-products.co.uk/1-overflow-rodent-and-insect-screen-bsp-female-thread-122-p.asp
Threaded fittings offer a strong, sealed connection and are often used in commercial and industrial water systems.
Why Choosing the Correct 1” Screen Matters
Selecting the right overflow screen is about more than just fit. It ensures:
Full, unrestricted overflow discharge
Effective rodent prevention
Insect ingress protection
Reduced debris build-up
Long-term system reliability
Rodents can squeeze through surprisingly small gaps. Even a poorly fitted screen can leave enough space for pests to enter. At the same time, an incorrectly sized unit could restrict water flow during heavy rainfall or tank overfill situations.
Small Component, Big Impact
Overflow pipes are one of the most overlooked weak spots in water tank systems. Whether your tank is used for domestic supply, rainwater harvesting, agriculture, or commercial operations, protecting a 1” outlet is a smart preventative step.
By accurately measuring your pipe and selecting the correct universal, compression, or BSP threaded overflow rodent and insect screen, you protect water quality, reduce maintenance risks, and prevent costly pest issues.
It’s a small upgrade, but one that delivers long-term peace of mind.
Frequently Asked Questions – 1” Overflow Rodent & Insect Screens
What does a 1” overflow outlet actually mean?
A 1-inch overflow outlet usually refers to the nominal pipe size, which is approximately 25mm–28mm depending on the pipe specification. It’s important to confirm whether this measurement refers to the internal diameter, external diameter, or a 1” BSP threaded fitting before purchasing a screen.
How do I know if I need a universal, compression, or BSP threaded screen?
This depends on your pipe connection type.
If you have a smooth pipe end, a universal connector is often the easiest solution.
If the pipe uses a mechanical tightening ring, you may need a compression fitting.
If your outlet is threaded, you’ll require a 1” BSP male or female threaded screen to match the fitting exactly.
Will a 1” overflow screen restrict water flow?
No, when correctly sized, a quality overflow rodent and insect screen is designed to allow full water discharge. The stainless steel mesh prevents pests from entering while maintaining efficient overflow performance.
Can rodents really enter through a 1” overflow pipe?
Yes. Rodents can squeeze through surprisingly small gaps, and overflow pipes often sit close to ground level. Installing a properly fitted screen prevents access and reduces infestation risks.
Are overflow insect screens necessary for domestic water tanks?
Yes, especially for cold water storage tanks and rainwater harvesting systems. Even if the main tank is sealed, an exposed overflow outlet remains a potential weak point.
Can I retrofit a 1” overflow rodent screen to an existing system?
In most cases, yes. Universal connector and compression models are specifically designed for easy retrofit installation without major pipe alterations.
How often should I check or maintain the screen?
It’s good practice to visually inspect the overflow screen periodically to ensure it remains clear of debris. In most environments, minimal maintenance is required.