How to clean a water bath

Instruction for cleaning and regular maintenance of water baths to prevent contamination.

Materials Needed:

• Commercial Bleach (Concentrated sodium Hypochlorite solution >6%)

• Distilled water

Personal protective equipment (PPE):

• Gloves

• Safety goggles

• Lab coat or apron

Safety Precautions:

• All laboratory safety protocols should be followed while cleaning the water bath.

• Gloves and safety goggles should be worn to prevent contact with bleach.

• Ensure proper ventilation when working with bleach.

• Do not mix bleach with other chemicals, especially ammonia-based ones or alcohol, as it can produce harmful gases.

• Keep the water bath unplugged and cool before cleaning.

Procedure:

1. Preparation:

   1. Use appropriate PPE, including gloves, safety goggles, and lab coat or apron, to protect yourself from potential splashes or spills.

   2. Ensure the water bath is unplugged and has cooled down before starting the cleaning process.

2. Preparation of Bleach Solution:

   1. In a well-ventilated area, prepare a bleach solution by diluting bleach with water at a ratio of 1:10 (1 part bleach to 9 parts water).
      
   2. For example, mix 100 mL of bleach with 900 mL of distilled water to make 1 liter of the solution.

3. Empty the water bath

   1. Carefully drain the water bath, disposing of any previous water and contaminants properly.

4. Clean inside of water bath, this should be done weekly

   1. Fill the water bath with prepared 10% bleach solution to approximately ¼ to the top.

   2. Moisten a clean cloth with the 10% bleach solution and gently wipe down the interior of the water bath, focusing on areas with visible residue, stains, or debris. Make sure to clean all surfaces, corners, and the inside of the water bath lid.

   3. Allow bleach solution to sit for 30 minutes to ensure complete sterilization.

5. Rinsing

   1. Dispose of dilute bleach solution in the sink with ample amounts of water 

   2. Rinse the water bath thoroughly with water multiple times to remove any traces of bleach. 

   3. Refill water bath with clean water.

6. Outer disinfection, should be done daily

   1. Moisten a clean cloth or sponge with 10% bleach and wipe down the outside of the water bath.  Allow the bleach to sit for 10 minutes. 

   2. Remove residual bleach/salt with a clean cloth moistened with water.

7. Drying 

   1. Ensure that the outside of the water bath, table and floor around the water bath are completely dry before connecting the water bath to its power source.

8. Verification

   1. Before using the water bath again, visually inspect it to ensure that it is clean, free of any residue, and dry.

9. Documentation

   1. Keep a log of the cleaning procedure, including the date, name of the person who performed the cleaning, and any observations about the condition of the water bath.