Potable Water Tanks
Fibreglass (FRP) drinking water tanks from 5,000L to 150,000L, certified to AS/NZS 4020 and made in Australia by Mullaly.
Fibreglass potable water tanks
Mullaly potable water tanks store drinking water for councils, water utilities, rural properties and commercial sites. They are underground fibreglass (FRP) tanks with integral ribs, made at our factory in Tomago NSW, and the tanks are certified to AS/NZS 4020 for products in contact with drinking water.
Single tanks run from 5,000L up to 150,000L for some applications, in diameters up to 3.28m, with single-wall and double-wall versions. They are designed for underground installation, and select above-ground installations. Where a site needs more storage than one tank holds, several tanks can be connected with PVC or fibreglass pipework.
Because the tank sits below ground, it takes up no yard or roof space and the stored water is out of direct sun. The fibreglass needs no lining or coating, so there is no liner to inspect, patch or replace over the life of the tank.
AS/NZS 4020 certification for drinking water
AS/NZS 4020 is the Australian and New Zealand standard for testing products that come into contact with drinking water. It checks whether a material changes the water it holds: its taste and appearance, whether it supports microbial growth, and whether metals or other substances leach into it.
Mullaly tanks are certified to AS/NZS 4020. For a specifier, it means the tank material itself has been tested for contact with drinking water, and there is no separate liner or coating in the design.
The certificate covers the tank. The water authority, health regulator or plumbing rules that apply to the site still set requirements for the system as a whole, such as backflow protection, overflow and vent arrangements, and disinfecting the tank before first use. Your hydraulic designer or plumber works those out for the project.
Where potable water tanks are used
Councils and utilities
- Council and utility water supply
- Water storage for remote sites and accommodation villages
- Emergency water storage for hospitals
Rural and commercial sites
- Rural and remote properties
- Commercial and industrial sites
- Sites with tight footprints, where an above-ground tank won't fit
Related tanks
For fire protection water, see our fire water tanks. For harvested rainwater used for toilet flushing and irrigation, see underground rainwater tanks. For factory wash-down and other non-potable uses, see industrial water tanks.
Potable water tank sizes and specifications
| Item | Detail |
|---|---|
| Drinking water contact | Certified to AS/NZS 4020 |
| Single tank capacity | 5,000L to 150,000L (the largest sizes for some applications) |
| Larger volumes | Several tanks connected with PVC or fibreglass pipework |
| Diameter | Up to 3.28m |
| Wall | Single wall or double wall |
| Installation | Underground, and select above-ground installations |
| Structure | Integral, high-profile fibreglass ribs, designed for the soil and surface loads on each site. Not limited by the water table |
| Material | Fibreglass (FRP) with resin that contains no fillers. No protective lining or coating needed |
| Accessories | Access risers, manways, inspection ports, FRP inspection ladders, baffles, and inlet, outlet, overflow and vent points |
| Quality | Made at our Tomago NSW factory, which holds ISO 9001 quality management certification |
Full details are in the water storage tank technical data sheet (TD_TDS_003). Tell us the storage volume, the site and how the water will be drawn off, and we will recommend tank sizes.
Why fibreglass for drinking water storage
No liner to fail
The fibreglass resists corrosion from the stored water and the surrounding soil, so the tank needs no protective lining or coating.
Watertight
Designed to be 100% watertight, so groundwater and soil stay out of the drinking water and the stored water stays in.
Rust and corrosion proof
There is no steel in the tank wall to rust, and the resin contains no fillers.
Not limited by the water table
Integral, high-profile fibreglass ribs give the tank its strength, and the ribs are designed for the soil and surface loads on each site.
No ongoing maintenance
The tank structure needs no ongoing maintenance or inspections.
Light to transport
A large-capacity tank ships on one truck bed and can be installed in remote places and tight footprints.
Planning a drinking water tank
To quote a potable water tank we need:
- Storage volume. The total volume, and whether it should be one tank or several connected together.
- Site conditions. Soil type, groundwater level, and what will be on the surface above the tank.
- Levels and connections. Inlet, outlet, overflow and vent positions, and pipe sizes, from the hydraulic design.
- Access. How many access risers, manways and inspection ports, and whether an FRP inspection ladder is needed.
- Delivery. Where the site is and any access limits for trucks and cranes.
Each tank is supplied with Mullaly's installation manual. For volumes above 20,000L see our large water tanks, and if you are weighing up a concrete tank, read fibreglass vs concrete water tanks.
Water storage tank photos
Potable water tank questions
Are Mullaly tanks suitable for drinking water?
Yes. Mullaly tanks are certified to AS/NZS 4020, the Australian and New Zealand standard for products in contact with drinking water. The water authority, health regulator or plumbing rules for your site may set further requirements for the system as a whole.
What is the difference between a potable and a non-potable water tank?
A potable water tank holds water for drinking, cooking and washing, so the tank material must not affect the water. Non-potable water, such as harvested rainwater for toilet flushing and irrigation or factory wash-down water, does not need to meet drinking water standards.
What sizes are available?
Single tanks run from 5,000L up to 150,000L for some applications, in diameters up to 3.28m, in single-wall or double-wall versions. Larger volumes are made up of several tanks connected with PVC or fibreglass pipework.
Does the tank need a lining or coating?
No. The fibreglass resists corrosion from the stored water and the surrounding soil, and the resin contains no fillers, so no protective lining or coating is needed.
Can a potable water tank go in below the water table?
Yes. Mullaly tanks are not limited by the water table. Their strength comes from integral, high-profile fibreglass ribs designed for the soil and surface loads on each site. Tell us the groundwater level when you ask for a quote.
Can you deliver to remote sites?
Yes. The tanks are light for their size, so a large-capacity tank ships on one truck bed and can be installed in remote locations and tight footprints.
Downloads
- FRP water storage tank technical data sheet (PDF)
- Single-wall water storage tank installation manual (PDF)
More documents are in the resource centre. Mullaly is part of the Tank Solutions group, and the same tanks are listed on the Tank Solutions site as FRP potable water tanks.
Download the water storage tank brochure
Enter your email and the brochure opens straight away. We will also email you the link.
Request a quote for a potable water tank
Send us the storage volume, the site location and any drawings. We reply to every enquiry within 2 business days.
Or call 02 4964 8270 or email sales@mullaly.com.au