Stored Water Treatment | UV-C Water Disinfection

Sani UV-C Submersible In-Tank Water Steriliser: Continuous Protection for Stored Water

A premium, locally manufactured UV-C disinfection solution designed for water tanks, reservoirs, borehole storage systems, rainwater harvesting setups and other stored-water applications.

Clean water is not only about what happens before water enters your tank. For many homes, farms, lodges, borehole systems and rainwater harvesting installations, the water is stored for hours or days before use. During this time, the inside of the tank can become an important part of the overall water-quality system.

The Sani UV-C Submersible In-Tank Water Steriliser is designed to work directly inside the storage vessel. Instead of treating water only as it passes through an inline chamber, the Sani submersible unit is positioned inside the tank, allowing UV-C exposure within the stored water volume itself.

This makes it a practical solution for customers who want a chemical-free way to support cleaner stored water in tanks, reservoirs, borehole storage systems, rainwater harvesting tanks, aquaculture tanks and processing tanks.

What Makes the Sani Submersible UV-C System Different?

Many UV water sterilisers are single-pass inline systems. These systems treat water as it flows through a stainless-steel UV chamber. That approach can be very effective for the right application, especially when water is being treated at point-of-use or before entering a building.

The Sani UV-C Submersible takes a different approach. It is installed directly inside the water tank, where it provides ongoing UV-C exposure to the stored water. This gives the system increased dwell or contact time, helping to reduce bacteria, viruses, algae and other waterborne microorganisms inside the tank environment.

For customers using borehole water, rainwater or stored municipal water, this makes the Sani unit a strong option where maintaining tank hygiene is just as important as filtering water before it reaches the tap.

How UV-C Works in Stored Water

UV-C light is used in water treatment because it can help deactivate microorganisms without adding chemicals, ozone or taste-changing additives. In a tank application, the submersible lamp is positioned inside the water storage vessel while the control box remains mounted externally for visibility, access and maintenance.

For best performance, the water should be filtered before UV-C treatment. Suspended particles, sediment and organic matter can reduce UV-C effectiveness because microorganisms may be shielded from direct UV-C exposure. Cleaner, well-filtered water allows better UV-C penetration and more consistent disinfection performance.

Available Sani UV-C Submersible Models

The Sani UV-C Submersible range is available in three model sizes. Choose the model according to your tank size and application requirements.

View & Shop Sani UV-C Submersible Units

Ideal Applications

The Sani UV-C Submersible is suitable for a wide range of stored-water applications where chemical-free disinfection support is required.

Start by Understanding Your Water Source

The best water-treatment setup depends on the source and condition of your water. Before selecting a UV-C system, it is important to consider what the water may contain before it reaches the tank.

Borehole Water

Borehole water quality can vary significantly depending on the area, depth and underground conditions. A water analysis is recommended where possible, especially if the water will be used for domestic, drinking or commercial purposes.

Municipal Water

Municipal water is generally treated before reaching the property. However, additional filtration and UV-C treatment can provide an extra layer of protection and may improve overall water quality where water is stored in tanks.

Rainwater Harvesting

Rainwater collected from rooftops can be a useful water source, but it should be filtered to remove leaves, sediment, organic matter and other particles before UV-C treatment.

Why Filtration Still Matters Before UV-C

UV-C treatment works best when the water is clear enough for the light to reach microorganisms effectively. Sediment, particles and organic matter can reduce UV-C performance by shielding microorganisms from exposure.

For this reason, the Sani UV-C Submersible should be viewed as part of a complete water-treatment approach. Depending on the water source, this may include sediment filtration, carbon filtration, specialised media, ultrafiltration, reverse osmosis or other treatment stages.

For a broader overview of how filtration works, what different filter types do, and how to choose the right system, read our guide: Water Filtration Explained: From the Basics to Choosing the Right System .

Maintenance: Replace the UV-C Lamp on Schedule

UV-C lamps naturally reduce in output over time, even if the lamp still appears to be switching on. To keep the system operating effectively, the lamp should be replaced approximately every 24 months or 9,000 effective operating hours, depending on system usage.

Zisabo stocks replacement lamps for all three Sani UV-C submersible models.

Shop Sani UV-C Replacement Lamps

How to Get the Best Results from UV-C Treatment

• Know your water source: Borehole, municipal and rainwater sources may require different pre-treatment.
• Filter before UV-C: Remove sediment, debris and suspended particles so UV-C can work more effectively.
• Choose the correct model size: Match the unit to your tank size and water usage.
• Allow adequate contact time: High water usage may require additional storage capacity or system sizing support.
• Maintain the lamp: Replace UV-C lamps according to the recommended service interval.
• Inspect filters regularly: Dirty or blocked filters can reduce overall water-treatment performance.

Important Safety Note

UV-C light can be harmful to eyes and skin. Do not switch on or test the UV-C lamp outside the tank. Always disconnect the power before installation, inspection, cleaning or lamp replacement. Installation and maintenance should be completed by a competent person.

Need Help Choosing the Right UV-C System?

Whether you are treating borehole storage, harvested rainwater, a JoJo-style tank, a reservoir or a commercial water-storage system, Zisabo can help you choose the correct Sani UV-C model and replacement lamp.