Looking for the ideal precast concrete water tank supplier? The task of a water tank is to reliably store water, keep it clean and safe and not leak or crack, and hold up for decades. If it does, then no one knows about it. If it doesn’t, the problem isn’t likely to be with the concept of the tank, but rather with the supplier that made the tank.
This Guide provides instructions on how to assess a precast concrete water tank supplier and ensure you have a water tank that will get the job done quietly, for years, whatever it is storing.
The Selection of a Supplier is More Than Simply About Capacity and Price
Generally, the first attributes that buyers compare is litre capacity, wall thickness and price per litre. A good starting point, but it ignores the real question: How does the supplier design, reinforce and cure the concrete so it can endure the constant water pressure and, as applicable, ensure that the water is safe for intended use?
Water tanks are subject of a challenging life, whatever their use. They are regularly filled and emptied, continuously wet from the inside, and frequently placed in the elements, where temperature changes and soil movement present additional stresses. A supplier with a vision of water storage as its own engineering discipline — not simply, “a big concrete container” — takes these stresses into account, and for potable use, of safe conditions within the tank. One who does not will give them a shiny new tank on delivery day and then one that begins to leak, crack or contaminate the water in two or three years.
Understand Exactly What Kind of Tank You Need for Your Project
It also is helpful to understand what type of tank your project really requires before comparing suppliers as suppliers do not necessarily make every type, and the specifications vary widely depending on the tank’s purpose.
Potable Water Storage Tanks
Potable tanks are used for water to be used for drinking or general domestic purposes and have the most stringent requirements for any type of tank. The need is for a mix design and finished product specifically designed for potable water contact, and certified to ensure the materials used are potable water safe for storage.
Underground Storage Tanks
Underground Tanks are tanks that are located below grade and are supported by the strength of the ground. They require proper cover reinforcement, watertight joints and a design that can withstand soil and groundwater pressure from the outside to the inside, rather than from the inside to the outside.
Above-Ground Storage Tanks
Above-ground tanks are used to store water for a variety of purposes: backup for domestic supply, fire protection or general utility supply and must have adequate wall thickness to resist the total hydrostatic pressure at the base and a level footing which must be stable.
Fire Protection Reserve Tanks
Fire protection tanks are water tanks that store a special bulk supply of water for the fire protection system and are subject to unique regulatory requirements for both volume and accessibility, and are inspected and regulated separately from the water storage.
After determining your project type (or types), you can limit your supplier search to manufacturers with specific experience in the project, especially for potable applications where general precast experience doesn’t necessarily translate to potable-safe experience.
Inquire About Their Water Retaining Concrete Mix Design
A water storage conscious supplier will not use a standard structural mix, but a mix designed specifically for water-retaining structures. This will generally involve low water-cement ratio, close packing of aggregates for reducing permeability and reinforcement cover that is appropriate for the expected moisture exposure as well as the structural load.
Explicitly ask the questions of permeability class the mix is designed for, reinforcement cover, and whether they use crack control such as fibre reinforcement or continuous waterstops at joints. If the use is potable ask specifically for certification that the mix and any internal coating is potable water safe. If the supplier responds with real numbers and – if applicable – real certification, then he or she is talking your language.
Explore How They Conduct Watertightness Testing Precast Concrete Water Tank Supplier
The most critical and most often overlooked item for any water storage tank is watertightness testing prior to delivery. Inquire if all the units are water-tested or hydrostatically pressure-tested at the yard or if the manufacturer relies on the mould and mix.
Some manufacturers fill and store all tanks before shipment and test for seepage at the base slab and at joints and walls. Some only use process consistency. Both ways may be acceptable, but “it should be fine” is not a test result and for a structure you are going to be burying, permanently plumbing into, or depending on for a critical water reserve “it should be fine” isn’t good enough.
Check Their Manufacturing Quality Control Procedures
Even two tanks with the same spec sheet on the side can be vastly different when it comes to their casting performance due to the casting process. Inquire about the procedure for casting, the curing process to take them out of the yard, and the inspection process prior to the tank being accepted for delivery.
Surfaces are more important here than buyers realize, especially if it’s a potable tank. A dense and well cured interior surface is much more resistant to the growth of algae, mineral staining and micro-cracking than a porous interior surface and in the case of drinking water applications, a clean interior finish is more important than cosmetic as it will not allow contamination. The information will provide you with a good deal of insight into the level of care being taken by a supplier’s production line.
Request Site-Specific Engineering, Do Not Request a Catalogue Sheet
Any good supplier will offer engineering calculations for your particular job that will not only be accurate but be tailored to your site. This should include inlet/outlet sizing based on the flow rates of your actual pump and distribution system, and structural loading according to soil conditions and groundwater table (for buried tanks).
Suppliers who can offer this sort of information will highlight site-specific concerns – expansive soils, seismic concerns, high water tables – prior to installation, instead of after the tank moves or cracks. If a supplier is not able to make the calculations for the project, you are probably purchasing a generic unit based on someone else’s conditions.
Compare Installation and Foundation Requirements Precast Concrete Water Tank Supplier
Installation requirements are much different for each tank type. A well-compacted level pad will suffice for some above ground tanks, and for larger capacity and underground tanks, special attention to the foundation of the tank, the specifications of the backfill, or anti-flotation measures may be necessary to prevent an empty tank from floating up under ground water pressure.
Inquire with your supplier if they need any foundation preparation, if they can give you instructions on how to prepare the foundation, or if they are willing to work with installers who have experience in their product, and what they expect to do if you have site conditions that differ from what they assumed in the original design. A surprise while inside the installation of needing a complete engineered base is an expensive one to have on-site for your “simple” tank.
Look at Their References and Their Track Record
Mix specifications and design standards inform you of what a supplier claims he or she can do. Once you’ve finished a project, it will tell you what it has actually delivered. Request examples to be provided for tanks delivered for similar size projects (and similar potable or fire protection needs) and ask for pictures that have been taken many years after the installation, not only at handover.
Take note of the performance of those tanks today. If a tank remains water-tight and sound after 5 years of use, it is a testament to a supplier’s true product quality more than any product brochure.
There Are Red Flags, Though, to Be Aware of to Help You Look Out for Them
Some warning signals seem to recur in less reliable suppliers:
- If asked about mix design, vague responses.
- No certification for tanks which are meant for drinking water.
- Hesitation to provide site-specific structural calculations before ordering.
- No apparent watertightness testing procedures prior to delivery.
- Pricing that is lower than competitive without a clear explanation.
Of course, none of these is a deal-breaker, but two or three together is the red flag to give the supplier the benefit of the doubt and ask some more questions before proceeding with a commitment.
Integrating All Aspects of Life Together Precast Concrete Water Tank Supplier
The key to the selection of a reliable water tank precast supplier is to know what you need, and to ensure that they are designing for water-retaining, long term use, using the correct mix design, with the tank proved to be watertight, sound manufacturing processes, proper certification for the type of use you are putting it to and real site-specific engineering behind each tank, rather than a data sheet.
If it can be done correctly, your tank will do what it was designed to do: reliably hold water year after year without anyone having to think twice about it.