With more than 30 years’ experience in the residential and commercial water treatment space, Mark Nelson is a Class 1 Drinking-Water Operator and a CBWA (Canadian Bottled Water Association) Certified Plant Operator. As founder and president of Nelson Water in Ottawa, Mark focuses on dealing with challenging water treatment system designs for problem water. He also heads the largest water bottling plant in the city of Ottawa with a delivery network throughout the Valley.

Water spots are caused by the mineral content in hard water supplied to your home. These minerals are primarily calcium and magnesium, and this is a common problem. A water spot is a white colored spot where the water has evaporated on a surface. This is especially noticeable on glass, but you can also see it on colored tiles and plumbing fixtures. Some people believe that water softeners can prevent water spots, but this is not true. Although a water softener can improve your home life in many ways, you will need to take some extra steps to deal with water spots.

Why Do Water Spots Occur?

Water spots are not caused by Total Dissolved Solids or TDS, but the higher the level, the more spotting that you will notice in your bathrooms. When we think about water hardness, we typically refer to the level of calcium and magnesium. But, in reality, these two minerals only represent a small part of the total mineral content of your water. The more accurate predictor of spotting potential in any source of water is the TDS level. This is because the salt used in an ion-exchange water softener can be left behind when the water dissolves. There are very real benefits to having a water softener in your home, including lowering utility bills, protecting appliances, using less detergent, and improving the condition of your skin and hair.

2 Main Contributing Factors of Water Spotting

There are two main contributing factors to consider when you’re thinking about water softener spots, they are:

  1. Water Softener Salt

If you have a water softener with an ion-exchange system, it needs salt to make the exchange. If your brine tank is low on salt or bridging has occurred, it can cause a number of other problems, including water spots. Salt bridging is when a hard crust of salt has formed near the top of the salt pile, and this is supported around the edges of the tank. Salt bridging causes a gap that prevents the salt from dissolving in the water, and this causes the water softener to stop working. This is easy to fix; simply break up the layer of salt carefully with a broom handle or other long object. Another common issue is salt mushing, which occurs when the dissolved salt has recrystallized and formed a sediment at the bottom of the tank. The only way to deal with the situation is to drain the system entirely and add fresh water softening salt.

  1. A Lack of Water Softener Maintenance

Like any complex system, a water softener requires some regular maintenance to work efficiently. Aside from the possible salt issue mentioned above, there are other problems that can prevent your water softener from working as intended. If the water softener is not working efficiently, it can allow hard water to enter your pipes, and this increases the chances of water spots. If you haven’t had your resin beds cleaned recently, they should be inspected by a local water treatment specialist. During the regeneration cycle, the resin beads are cleaned, but over time the media needs to be professionally cleaned to maintain efficiency. Another potential problem is your water softener settings that can affect the quality and operation of your water softener.

Can a Water Softener Reduce the TDS Level?

A water softener is designed to reduce the level of hard mineral content in your water. As such, it won’t have much of an effect when it comes to reducing the overall level of TDS. The minerals that are “removed” will be those that cause the water to be hard, including calcium, magnesium, and to a lesser extent, iron.

Many people believe that a water softener removes the mineral content from their water, but this is a misconception. The most effective method of water softening is an ion-exchange method which uses softening salt and a resin media bed. As the name suggests, the mineral ions that cause hard water are exchanged for sodium or potassium ions that are more benign. Both sodium and potassium are salts, but some people that are sensitive to salt are more inclined to use potassium.

Water that has high levels of TDS will leave behind more water spots. This is because every mineral ion that needs to be exchanged will be effectively replaced with a sodium or potassium ion. So, it’s important to understand that the higher your TDS level, the more softening that will be required to make it soft. But, high TDS water will produce water spots whether you soften it or not, and there may be other solids left behind in your water. This can often be observed as a residue or film, and that is what you see when you notice a water spot.

Can Softened Water Remove Spots?

The short answer is no. Although softened water is far superior to hard water when it comes to bathing and cleaning, and extending the useful lifespan of plumbing and appliances, it will not remove spots. But, the spotting that you notice when you have soft water with an overall high TDS level may actually be spots of sodium or potassium. There may still be spotting, but these residual water softening salt deposits are much easier to remove with a simple wipe of a towel. This is very different from spots caused by limescale and soap scum which may require a lot of scrubbing to remove.

Can I Get Water That Doesn’t Cause Any Spotting?

Yes, the best type of water to use when you wash your car is from a Reverse Osmosis (RO) filtration system. This type of filtration passes the incoming water through a semi-permeable membrane under pressure. Only pure water molecules can pass through, which means that RO water is virtually free from all mineral content. In fact, a RO system can remove many types of contaminants, including fluoride, chlorine, bacteria, heavy metals, and more. You can invest in a whole house RO system, but even a simple under the sink unit will provide sufficient water to wash your car without spotting.

If you want to install a RO system in your home or need some essential maintenance for your water softener, contact your local water treatment specialist today.