Sizing & How Does a Water Softener Work?
What is a Water Softener?
A water softener is a device that reduces the hardness of the water. A water softener typically uses sodium or potassium ions to replace calcium and magnesium ions, the ions that create "hardness."

Education - What is Hard Water?
Commonly known as lime or scaling, hard water is composed of calcium and magnesium and leaves scaling white deposits on faucets, tubs, sinks and lines the inside of a hot water tank reducing it's efficiency. Hard water is found in areas that are composed limestone. Calcium and magnesium are absorbed into the water as it comes in contact with the limestone. This occurs most commonly in deep wells and can occur in lakes with spring feed water sources.
Benefits of Soft Water

Symptoms of Hard Water

Benefits of Softened Water
Fading Colours in ClothingBetter Lather for Bathing
Film on the DishesLess Conditioners
Spots on the SinkBrighter Colours in Laundry
Dry Skin After ShowingSoap & Cleaner Savings
Scaling in Kettles or PotsImproved Water Heater Efficiency
Slow Flow at Shower HeadSpot Free Dishes and Fixtures

Proper sizing of a water softener is important to maintain continuous soft water in a home all year

What Size of Water Softener?
Household water softeners are rated by the number of grains of hardness they can remove through a specific volume of resin in the tank, and the amount of salt needed to regenerate the resin. To find the right size of softener for your household you will require two things:

Your average daily household water use not including outdoor watering
The average grains per gallon of hardness in your tap water

1. Calculate your Average Daily Household Water Usage
Method 1: The average person consumes between 167 and 195 litres (44 and 51.5 US gallons) of water per day, respectively. Consider your water usage characteristics and use 50 gallons if you are unsure. To calculate your daily household water use, multiply your average per person water use in gallons by the number of people in your household. 

ie: 4 people x 50 gallons = 200 gallons per day.

There is no need to “add a person” to your calculation for dishwashers.. Households with dishwashers use less water than households washing dishes by hand!

2. Find the Water Hardness
Water hardness is measured as grains per U.S. gallon (1 grain = 17.1 milligrams per litre). Residents connected to municipal water supplies can find their average water hardness by contacting their local municipality.

IdeaIf you’re on a private well, you’ll need to have your hardness and iron tested separately in order to calculate your hardness rating. You may need to increase your grain hardness rating to compensate for iron in your water. For every one (1) mg/l (milligrams per litre) of iron, three (3) grains per gallon (gpg) of hardness needs to be added to the total hardness value.

Water Hardness

Test for water harness annually to detect any changes in your water quality

Calculate your Daily Hardness Removal Requirement
Multiply your household’s average daily water use as calculated in step one, by the grains of hardness in your water found in step two. To calculate your daily hardness removal requirement:

How a Water Softener Works
Calculating Water Grains

Ideally a water softener should remove hardness from the water for seven days before needing to regenerate. Simply multiply your daily hardness removal requirement by seven to calculate the suggested water softener size. Although water softener sizes vary, the table below gives some of the more typical sizes of softener available for a range of daily grain requirements.

Daily Grain Requirements        Suggested Softener Size
0 – 3,500 grains per day                         24,000 grain capacity
3,501 – 4,500 grains per day                 32,000 grain capacity
4,501 – 5,750 grains per day                 40,000 grain capacity
5,751 – 6,850 grains per day                 48,000 grain capacity

Using the formula above, a family of three using 60 gallons of water per person per day, with a water hardness of 23 grains per gallon, will need a softener that can remove 4,140 grains of hardness per day. Over seven days, the softener would need to remove 28,980 grains of hardness. The suggested softener size for this family would be one with a 32,000 grain capacity.

Best Practice Recommendation
If you own or are considering purchasing a water softener, knowing the hardness level of the water is important to ensure that your system operates correctly and provides continual soft water in your home. If you are unsure about your water quality or have questions, consult a certified water treatment professional who can provide you with assistance in selecting or maintaining a water softening system properly.

Volume 6 - Issue 3 Wahl H2O - Water Awareness
Copyright 2022 Jeff Wahl – Wahl Water | All Rights Reserved
Contact Jeff via email [email protected]

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