Searching for the ideal Precast Concrete Irrigation Water Tank Supplier?
On paper, the job of an irrigation tank is a simple one: store water, send it out at a time, and forget it for decades.
If it functions properly, no one is aware.
When it fails, it’s not because they didn’t have the right idea—it’s for the most part because of the supplier that it was built.
This guide explains how to evaluate a precast concrete irrigation water tank supplier to ensure that your farm, estate or agricultural project has a tank that performs its function without making a lot of noise for years to come.
The Capacity Rating of a Tank Is Not the Only Factor When Selecting a Supplier
The first thing most buyers compare among the various models is the amount of litres, the thickness of the walls and the cost of each unit.
It’s a good assumption to make, but it misses the point: How does the supplier design, reinforce, and cure the concrete, and ensure it’s water-resistant — and endures — over the years of wet/dry cycles and hydrostatic pressure?
Irrigation tanks do not have the glamour of most people think. They are filled and emptied over and over again, fertilized by discharge, infested with contact with groundwater, and in many areas exposed to extremes of temperature which dry and crack poorly cured concrete.
Any supplier that thinks about irrigation storage as a whole, not as “a big concrete box”, will take these stresses into account when designing.
The one that doesn’t will deliver a tank that looks like a hunk of perfection and then begin to leak or crack after a couple of seasons of irrigation.
Understand the Type of Tank That Your Project Requires
The first step is to be familiar with the different types of tanks so you can compare suppliers because not all precast manufacturers produce all types of tanks.
Underground Storage Tanks
Underground tanks for irrigation are housed below grade, and are built with their structural strength and not by their appearance.
They must have good sealant reinforcement, watertight joints and a design that is resistant to soil and groundwater forces acting from the outside rather than from the inside.
Above-Ground Storage Tanks
Above ground tanks hold more water and usually are used to serve a drip or sprinkler irrigation system.
They should be strong enough to withstand the total hydrostatic load at the base, and have a stable level base footprint to ensure an even settling over time.
Sectional or Modular Tanks
For access and size reasons, sometimes a single monolithic pour is not feasible, which is where sectional tanks are beneficial; they are constructed on-site by joining precast panels together.
Their performance is highly reliant on the quality of the joint sealing system because this is where most failures of modular tanks begin.
Water Is Collected in Sump and Collection Tanks for Further Use
The runoff, drainage or reused irrigation water is collected in sump or collection tanks prior to being pumped back into the water system.
They put more emphasis on inlet/outlet placement and internal baffling for good flow design as compared to sheer volume because poor flow design results in sediment building up and pump strain.
If you’ve determined which category (or combination) your project fits into, then you can begin to narrow your list of suppliers to those who specialize in providing agricultural and irrigation storage, not just a piece of the general precast catalogue.
Inquire About Their Water Retaining Concrete Mix Design
An irrigation storage-aware supplier will not be using a stock standard structural mix with a waterproofing admixture slaked into it but rather a mix specifically formulated for water-retaining structures.
This usually involves a low water/cement ratio, close packing of the aggregates to reduce permeability, and reinforcement cover appropriate for exposure to moisture rather than structural load.
Inquire specifically for the permeability class the mix is designed for, reinforcement cover, and use, or not, of crack-control materials such as fibre reinforcement or continuous waterstops in joints.
When a supplier responds with actual numbers, he/she is speaking your language.
Someone who just uses “strong, durable concrete” without any specifications is a guy to watch.
Review How They Handle Watertightness Testing
The most important (and frequently omitted) test for any tank to be used for watering is watertightness prior to delivery.
Do all units undergo water testing at the yard or do the suppliers assume it will work because of the mould and mix?
Some manufacturers check for seepage at the base slab joints and walls, and fill and store all tanks prior to shipping.
Others use only the consistency of process.
Both methods can be used, but it is not the same as a documented test result, and for a structure you are burying or permanently plumbing into your irrigation system, you want the documented result.
Examine Their Manufacturing Quality Control
Two tanks might be the same specification, but be very different when actually cast.
Inquire about the casting of a unit, how long it is cured before it comes out of the yard, and what steps are taken to inspect the unit before it is approved for delivery.
The surface finish is more important than customers realise.
The well-cured interior surface will resist algae, minerals and micro-cracking much better than the porous surface, and clean corner and joint detailing will minimize risk of chipping during transport or crane placement.
When you read all this information you will see how seriously a supplier treats its production line.
Request Site-Specific Engineering, NOT a Catalogue Sheet!
A competent supplier will be able to supply engineering calculations for your site and not just a standard product datasheet.
For irrigation tanks, it should include irrigational structural loading, depending on the soil conditions, level of the groundwater table in a buried tank, and the correct sizing of the inlet/outlet pipes to suit the actual flow rates of the pump and distribution system.
Suppliers who can offer this information will be able to identify site-specific problems, such as high water tables, expansive soils, seismic requirements, before installation, instead of after a tank has shifted or cracked.
When a supplier cannot generate project-specific calculations, there’s a good chance that you are purchasing a generic unit that has been created based on other conditions.
Focus on Similar Installation and Foundation Requirements
Requirements for installation will differ greatly depending on the type of tank.
In some above-ground tanks only a compacted level pad is necessary, but in other tanks, such as those that are buried or larger in capacity, engineered foundations, backfill specifications and anti-flotation devices may be required to prevent an empty tank from lifting due to hydrostatic pressure from the groundwater.
Ask your supplier what foundation prep will be needed, whether they give you installation instructions or whether they work with installers who are familiar with their product and what they assume about your site conditions, how they are applied, or what they do if they are not.
Having to discover that your “simple” tank requires a full engineered base, after you have already installed the tank, is a costly on-site surprise!
Look at Their References and Record
Mix specifications and design standards provide information about what a supplier is capable of.
You can see in completed projects what they’ve really delivered.
Seek and provide examples of irrigation tanks provided for projects of similar size and scale in a similar climate/soil environment as well as pictures of the irrigation tank 1+ years after it has been installed (not just at handover time).
Take note of their performance with those tanks at this time.
When a tank remains water tight, and structurally intact after just a few irrigation seasons, it’s a reflection of the supplier’s real quality, not any product brochure.
The Following Are Some of the Red Flags to Look Out For
Some of the clues that do not appear to change across less reliable suppliers are:
- The answers are vague when asked for a mix design or permeability class.
- Supply of site specific structural or foundation calculations is insufficient or delayed.
- No watertightness testing process is documented prior to delivery.
- Pricing is significantly lower than that of competing suppliers, but with no rationale for this.
None of these should be a deal-breaker, but two or three in combination should give you cause for pause to inquire more deeply before signing with that supplier.
Educating Students to Bring All the Pieces Together
The key to selecting the right precast concrete irrigation water tank supplier lies in understanding exactly what is needed for your project, and in ensuring that the water tank supplier has designed the water storage tank specifically to be used for water-retaining, long term outdoor use: with a water tank supplier that can provide a water tank to your project with a proper mix design, verified watertightness, sound manufacturing practices and real site-specific engineering behind the water tank, not just a data sheet.
If you get it right, your tank does exactly what it’s supposed to: sits in the ground or on the pad, reliably holding water, year after year, with no one even needing to think twice about it.
