So your home or business had the water tested and determined that you have hard water and need a water softener. The next step might be the most challenging if you don't have any experience: how to get the right size water softener.
There is a lot of terminologies associated with sizing a water softener that many people are not familiar with. Terms like flow rate, water capacity, grains per gallon, and cubic feet of resin may sound like a foreign language. But, don't worry, we are here to walk you through each step on how to get the right size commercial or industrial water softener.
How Hard is Your Water?
The first step in determining what size water softener you need is to get your water tested. If you're confident, you can test the water yourself using water testing strips you can buy from Amazon, Home Depot, and other retailers.
However, these tests are not always accurate or easy to read so getting a lab or a licensed professional to test your water may be a better option to get accurate results.
Water hardness is commonly reported in milligrams per liter (mg/L) as calcium carbonate. Note the value of calcium carbonate in the report and compare it to the following scale used by the U.S. Geological Survey:
- Soft water: 0-60 mg/L
- Moderately hard water: 61-120 mg/L
- Hard water: 121-180 mg/L
- Very hard water: Over 180 mg/L
How Much Water Do You Consume?
Once you determine how hard your water is, it is time to figure out how much water your home or business consumes. The best way to get accurate results is to look at your monthly water bill to see how much water your home or business is consuming each month.
However, if you don't have your bill, a good rule of thumb is to use 70-100 gallons per day per person in your home. This will give you a fairly accurate number to base your calculations off.
Commercial and industrial properties are a little tough to estimate simply because some businesses use a lot more water than others in their day to day operations. Also, a small business typically will use a lot less water than a large business with more employees and water-using appliances.
We recommend all businesses reach out to a water treatment professional to help determine the size of water softener they need.
Determining Water Softener Capacity
Water softeners are full of small plastic beads called resin. These resin beads remove hard water minerals by pulling them out of the water, much like a magnet. They do this by using ion-exchange.
All the resin beads are negatively charged and hold sodium ions. As the water passes over the resin, the resin prefers the more strongly charged calcium and magnesium ions, rather than the weaker sodium ions. The displaced sodium ions then pass through the resin bed and out the softener outlet, thus delivering soft water.
A water softener’s capacity is based on the amount of resin inside the unit. 1 cubic foot of resin can remove 32,310 grains of hard water minerals (calcium, magnesium, iron, and manganese). Common residential sizes include 0.75, 1.0, 1.5, and 2.0 cubic foot systems
Once a system has reached capacity, the resin beads will be covered with minerals, and be incapable of softening the water. At this point, the system will have to clean itself out with salt (also known as regeneration) to resume softening.
How Often Do You Need to Regenerate?
Many factors go into determining how often your softener will need to regenerate, or clean itself, with salt. Water hardness, volume, softner size, and more all need to be considered.
A softener that is too small may need to regenerate more often and will decrease its lifespan. By contrast, a softener that is too large may be overkill for what your home or business needs.
The best way to get the correct regeneration frequency is to get a metered valve. A metered water softener valve will measure the amount of water you use, and will try and regenerate often enough to keep up with usage.
Time to Do Some Calculations
Once you understand the terminology and have the numbers, it is time to do some simple(well, kind of simple) math. Here is an example:
5 people in a home with 10 grains per gallon hardness.
- 5 people X 70 gpd = 350 total gpd
- 350 gpd X 10 grains = 3500 grains per day
1 cubic ft. @ 24,000 grains / 3500 = 6.8 days between regenerations
1.5 cubic ft. @ 32,000 grains / 3500 = 9 days between regenerations
2.0 cubic ft. @ 40,000 grains / 3500 = 11 days between regenerations
The best choice would be the 1 cubic foot unit water softening system with close to a 7-day regeneration schedule.
Conclusion
While we hope this helps you better understand how to size a water softener, we know this will by no means make you an expert. We still highly recommend that you contact a professional to help you get a system that is best for your home or business.
A licensed professional may determine you have other minerals or contaminants that a water softener will not be able to take out. Things like iron may need a filter or a Reverse Osmosis system to filter out. This is particularly critical if you get your water from a well or a private source.
Robert B. Hill Co has been helping businesses and residents get the right water softener for over 60 years. Contact us today and we will be happy to assist you in sizing a water treatment system or getting you a custom quote for your business.
