Water Softening

Meeting Restaurants’ Water Needs

Imagine you are seated at the table for a highly anticipated meal out with family and friends, and you are confronted with all restaurants’ nemesis—spotty flatware and glasses. While not a significant matter in the grand scheme of life, still it is an annoyance and a poor start to any dining experience. First impressions create lasting assumptions about the overall quality of the eating establishment. The most common cause of these spotting problems is our old friend, hard water.

Hard Water

Hard water in restaurant applications causes aesthetic spotting problems in addition to the inherent financial burdens. The scale formation and insulating barrier developed by hard water deposits results in higher maintenance expenses and lost heating efficiency. The cost of added dishwasher cleaning products is greatly increased when using hard water, and typically far exceeds

the cost of a softening system. Unfortunately, restaurants’ hard water problems are far too often
the result of improperly applied
or sized softening equipment.

Due to highly variable daily water use, a twin-alternating, meter-initiated system is almost always the best choice for restaurant applications. Single meter-initiated systems are difficult to size because they require a full day’s reserve capacity. This would make the softener larger than needed and far less efficient than the twin-alternating version. Legislation restricting softener use is partly a result of the wasteful systems that “we” install. Properly applied, a twin-alternating softener will use far less salt and regenerant water than other system types and it is more environmentally friendly.

Water Benefits

The primary benefits of restaurant softened water are realized on the hot water side. Therefore, softeners are typically installed to the influent of the water heater. Be sure to plumb the system correctly to prevent hot water from “backing up” into and damaging the softener. Some cold water benefits can also be attained, but due to the initial cost, the cold water is normally not softened. There are many opportunities in a restaurant for small and remote softeners and filters. Drinking water, ice tea makers, ice machines and espresso machines are a few examples. Many factors, such as frequent maintenance requirements, highly discourage the use of hot water fed softeners dedicated to the dish machine.

For sizing purposes, copies of one year’s water bills can be quite illuminating in attaining an average-use figure. In lieu of that, use an estimate of 4–5 gal. of hot water per customer per day. Add 2 gal. per day per customer if there is a separate lounge. For full line use, 10–12 gal. per day per customer is typical. It is best to install a brine tank large enough to hold the needed amount of salt until your next scheduled delivery. If you do not offer a salt delivery service, you will have to depend on the customer maintaining an adequate salt supply in the brine tank. The high peak flow-rate requirements of large sinks and other water-using stations will require the softener to be sized appropriately not just for capacity needs, but also to accommodate the peak flow demands. When undersized, it is amazing how quickly a restaurant employee discerns that increased flow can be achieved by opening the softener bypass valve.


Spots caused by hard water are generally difficult to wipe off, while spotting or residue from poor dishwashing machine performance will wipe off with little effort. Do not be afraid to leave a good quality test kit with the manager. This will allow the manager to test the water and know whether to call the water treatment dealer or the dishwashing representative in the case of spotting problems. It is mutually beneficial to work with the dishwashing machine/chemical representative to solve problems rather than play the blame game. Soft water will not quickly remove existing hard water spots, so use a readily available scale/hard water removing cleaner to give the dishes a fresh start.

Softener Problems

Restaurant softeners will suffer all of the standard maintenance problems, plus a few that are more unique. Pre-rinse sprayers in the kitchen are notorious for mixing hard/cold and soft/hot water supplies. This not only causes hard water problems, but also provides a constant supply of cold water into the circulating hot water system. This results in more energy being required to keep the circulating hot water heated. When this occurs, you will probably find that the water directly out of the softener test bib is soft, but that the hot water in the building is only partially softened. Check for this problem by running the pre-rinse sprayer with both the hot and cold controls in the on position until the feed pipes under the sink are distinctly hot and cold. Release the sprayer nozzle and monitor the hot water pipe to see if it turns cold within about one minute. The hard/cold water passing through the sprayer mechanism being drawn into the hot water line by the circulating pump causes this. The sprayer mechanism needs to be repaired, or a one-way check valve can be installed on the hot water feed pipe to the pre-rinse sprayer.

Portable exchange tanks are often used in place of the more standard on-sight regenerating softeners. Portable exchange tanks face capacity issues as it is difficult to accommodate for peak water use periods. However, they eliminate the on-sight salt concerns. Typically installed in parallel, it is important that the plumbing be balanced to promote equal flow through each tank. Water will take the path of least resistance, so if the resin quality varies from one tank to another, or if the piping configuration makes a less resistant path, the water will tend to follow that route. Testing the effluent hardness of each tank upon exchange can provide valuable information as to whether there is a balanced flow through the tanks.

In conclusion, default to using meter-initiated, twin-alternating softeners whenever possible. Have an easy-to- use, well-marked bypass so the customer can turn the softener off in an emergency while still providing water to the facility. Sizing adequately for peak flow and capacity results in proper performance and satisfied customers. Restaurant applications pose some extra challenges, but with proper preparation and equipment you can make this a very profitable part of your water conditioning business.