In-house Quality Control Testing for Bottled Water Plants

Oct. 28, 2019

Areas bottlers need to focus on for quality control purposes

About the author:

Barbara Marteney is a beverage accounts manger for National Testing Laboratories, Ltd., Cleveland, Ohio. Marteney is actively involved with NEBWA and is currently a member of IBWA’s Government Relations and Supplier Committees. She can be reached at 800.458.3330, ext. 217, or by e-mail at [email protected].

Updated 10/28/19

When developing a quality control program, bottlers must evaluate many facets of their operation including sources, transportation, supplies, ingredients, equipment, maintenance, product and distribution. The three major areas to focus on for in-house quality control testing are process, packaging and product.

In-house testing for quality control purposes is a critical part of a bottled water business. The data accumulated is an invaluable tool for detecting problems in the process, heading off potential problems and troubleshooting product quality complaints. When a customer complaint comes in, this data can be the first line of defense. Accurate, organized and detailed records of daily testing and process quality checks give the bottler a path to follow in either ruling out a problem in the process, or pinpointing where a product quality problem may have originated. Then any necessary corrective action procedures can be developed and implemented.


Determining what points in the process to test should coincide with the bottlers’ Hazard Analysis and Critical Control Points (HACCP) plans. HACCP is a prevention-based program that identifies and assesses hazards associated with the process, determines the critical control points in the process for the identified hazards, and establishes a monitoring system for these points. There are many points in the bottling process that could be monitored as a control point or a point in the process where the product quality could be at risk. A critical control point is slightly different in that it is the last point in the process where a particular problem could be avoided. For example, transportation of source water to the plant has potential risk for microbiological contamination, but it would not be a critical control point for bacteria testing if the water is ozonated or otherwise disinfected at a later point in the process. The last point of disinfection would be the critical control point or most critical area of concern for monitoring in order to prevent the possibility of microbiological contamination in the final product water.

Frequency of testing performed to ensure that all of the equipment in the process is operating effectively should be determined based on manufacturer recommendations. Equipment and process monitoring is case-specific a different plants have their own specific configurations and products. Generally, checks should be performed at start-up each day or at the beginning of each shift and then at regular intervals throughout each production run on all equipment used in the process such as those discussed below. Filtration/demineralization processes—sand, carbon or particle filtration, distillation, reverse osmosis, deionization (depending on the process and water type) call for tests on:

  • Delta P (measures drop in water pressure);
  • Conductivity;
  • pH;
  • Chlorine removal;
  • Taste;
  • Turbidity;
  • Chloride;
  • Resistivity; and
  • THMs.

    Bottle washer monitoring should include testing of:

  • Cleanser concentration;
  • Cleanser carryover in bottles;
  • Pressure;
  • Temperature;
  • Rinse and wash volume; and
  • Visual inspection of jets (direction and flow).

Lot numbers of raw materials/ingredients/packaging materials should be documented upon receipt and at time of use for traceability.


Packaging equipment, such as cap and label applicators and date coder operation efficiency, should be inspected regularly for correct application, legibility and accuracy. Contents of the filled product bottles should be verified regularly based on volume or weight.

Container and closure samples should be pulled from the production line (just before filling) and tested quarterly to be sure they are free of bacterial contamination. Four samples of each type of bottle and each type of cap used should be tested quarterly.


When referring to product quality monitoring, beginning, middle and end of a production run is a common reference. This refers to bracketing or dividing up the production run. These brackets may be defined by certain events such as performing microbiological testing or by label changes within a production period. Quality monitoring is then performed and documented within these bracketed periods. This can be useful in breaking up large production runs to make it easier to trace a potential problem. In case of a recall, the scope could be limited to that specific time period of the production run (if the times are included in the date codes used on the bottles).

Product quality monitoring should be set up on a regular schedule throughout the production run, or bracketed period, dependent upon the parameter and the type of water being produced. The following tests are typically recommended for in-house product water testing (some are specific to certain types of water, such as fluoride). Testing frequency for these parameters is usually at production start-up and at regular intervals throughout the specified production period.

Conductivity. Monitor conductivity frequently to confirm product consistency. Taste. Perform periodic testing to determine that the taste remains pleasant. pH. Natural waters should remain within a pH range of 6.5–8.5 (purified/ distilled/RO usually fall into a lower pH range of 5–7).

Fluoride. Fluoridated product water is generally tested at start-up and a couple of times per shift to ensure consistent levels. If the fluoride is naturally occurring, levels should be around 2 mg/L (1.3 mg/L if it is being added to the product water).

Ozone residual. Recommended monitoring is every 1/2 hour. A spike in ozone levels can lead to product quality problems depending on the chemical makeup of the water being ozonated. Ozone residual should fall between 0.1 and 0.4 ppm. The appropriate level for a particular water should be determined based on the water chemistry and regular microbiological testing. Various adjustments coinciding with testing of ozone, micro and bromate may be required to determine the appropriate levels.

Microbiological. Weekly coliform testing should be done on source and product waters by an approved laboratory. Some bottlers have their in-house labs approved by the state for coliform testing, but most send it to a certified laboratory. In addition to satisfying regulatory requirements, these independent results offer a check and balance against the in-house test results. Bottlers using a municipal source don’t have to do the weekly testing on the source as it is already tested by the municipality. The finished product water should be tested in-house by the bottler daily. Testing may also be done more frequently in order to bracket production runs.

Detailed records of the quality monitoring program tests should be maintained on-site for at least five years.

These recommendations are not all encompassing for every type of facility and/or type of water produced. Bottlers should consult their equipment suppliers, regulators and/or a consultant who is experienced in the bottled water industry about the in-house quality monitoring program that is appropriate for their facility.

The International Bottled Water Association (IBWA) is an excellent resource to bottlers for information and tools to help develop effective HACCP plans and quality control programs. Bottlers can get information from the IBWA website at

About the Author

Barbara Marteney

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