Conserving water is an important way that restaurants can reduce their environmental impacts and operating costs. Water use is an important aspect of operations and is used largely for food preparation and sanitation purposes. The following section will examine water conservation across four areas of operation:
- Changing Practices
- Equipment and Fixtures
Perhaps one of the easiest and most cost effective ways to conserve water is to focus on staff behaviors and accepted kitchen practices. Is it necessary to defrost food using running water? Is it necessary to automatically serve water at each table or could it be something that you serve upon request? Little things can go a long way.
Equipment and Fixtures
It is important that all equipment is installed and operated in accordance with manufacturer instructions. Water flow rate should be near the minimum recommended by the manufacturer to use as little water as possible while still ensuring excellent equipment performance.
For moderate to high hot water needs, consider a refrigerant heat recovery system, which recovers heat from walk-in refrigerators and freezers for kitchen use.
a. Pre-Rinse Spray Valves
The Alliance for Water Efficiency recommends the use of low-flow high efficiency pre-rinse spray valves. Standard spray valves flow at about 3 gallons (11 litres) per minute (gpm) and are used an average of 1 to 4 hours each day. The flow rate of efficient models is only 1.6 gallons per minute (6 lpm) or less. These efficient units can save the average small to medium foodservice operator as much as 150 gallons of hot water per day and are equally effective in cleaning. Replacement spray valves generally cost less than $50 and last about five years.
b. Tap Aerators
Install tap aerators in faucets to offset high water use in sinks. These are relatively inexpensive and can be readily purchased at any hardware store. The Food Service Technology Center recommends the use of 0.5 gpm aerators. Costing only a few dollars, a single hand sink retrofitted with a 0.5 gpm aerator can reduce annual energy and water costs by $100.
Commercial dishwashers use the same amount of water and energy regardless of how full they are so it is important to run full racks of dishes. As well, high-temperature dishwashers should be turned off at night. Otherwise the booster heater will consume energy keeping the hot water tank at temperature.
The Alliance for Water efficiency states that efficient dishwashers should use less than 1.2 gallons of water per (20-in by 20-in) rack for fill-and-dump machines and less than 0.9 gallons per rack for all other types of machines. For under-the-counter machines, water use should not exceed 1 gallon per rack for high-temperature machines and 1.7 gallons per rack for low-temperature machines.
d. Combination Ovens
According to the Food Service Technology Center, (FSTC) a typical boiler-based combination oven uses up to 40 gallons of water per hour! This water is being used regardless of whether the oven is cooking, and much of it goes straight down the drain. A boiler less combination oven will deliver the same product quality while using much less water. These ovens can cut water usage to as low as 20 gallons of water per hour or less. And, ovens that use less water typically use less energy as well.
Operating Tips for Combination Ovens (adapted from the FSTC)
- Use the oven’s programming capabilities to control different cooking modes to maximize energy efficiency and cost savings.
- Use combi mode sparingly and only when necessary.
- Turn the oven down or off during slow times. By cutting out two hours of idle time per day it can save $400 to $800 annually
- Keep the doors closed all the way and cook with a fully loaded oven.
e. Ice Machines
According to the Arizona Department of Water Resources, Water Efficient Restaurant Technologies (2009), a typical ice machine uses about 130 to 180 gallons of cooling water to make 100 pounds of ice. When selecting an ice machine, choose an efficient model that uses approximately 20 gallons of water per 100 pounds of ice produced. Flake ice machine are very efficient and use 12 gallons of water per 100 pounds of ice produced. You should also select air-cooled models over water-cooled models.
Water conservation in restrooms centers largely on the use of low flow toilets and urinals and the use of tap aerators.
When replacing toilets, select low-flow high efficiency models that use a minimum of 1.28 gpm. Consider dual flush versions as well to further reduce water use.
When replacing urinals, select a low flow version using a minimum of 1/8 gpm flow or instead choose a waterless model.
c. Tap Aerators
Ensure that faucets are equipped with tap aerators to improve water efficiency. Also, consider using faucets that are touch-less or automatic where water flow is set for a specified amount of time.
- Check rinse water temperature regularly to ensure proper operation of the booster heaters.
- Regularly clean lime deposits from hot water tanks and heater coils.
- Set up a system to report leaks and fix them immediately. Require cleaning staff to report problems.
- Immediately replace any damaged dishwasher racks.