I was on a water loss this week, standing in a kitchen looking at a clean break on a supply line under the sink. The contractor looked at the puddle on the floor and said, “I wouldn’t drink that. It’s a Category 3.” One of the technicians nodded and repeated a line that gets used a lot on jobs: “If you wouldn’t drink the water, it’s not Category 1.” It sounded logical to them on the surface, but I knew it was not how the ANSI/IICRC S500 defines categories of water. I also knew that when scope, PPE and pricing are based on a “drink test,” the project is off the standard and the restorer is opening the door to challenges from adjusters, TPAs and consultants. 

So, I started walking them through the loss. I told them the standard does not care whether anyone would pour a glass and drink from the loss water. It classifies water based on where it came from, what it comes into contact within the building, how long it has been present and at what temperature and whether contaminants are present that would not normally be expected in a typical indoor environment. In simple terms, the category of water is about the level of contamination, not personal preference or appearance. Technicians and project managers are expected to think about undesirable substances in the water that can impact health through skin contact, breathing or ingestion, cause damage to the structure, systems and contents or interfere with the normal operation of building systems. That is a very different test than “Would you drink it?” 

We walked over to the broken supply line, and I explained that Category 1 water starts from a sanitary source and is not expected to pose a substantial risk from normal dermal, inhalation or incidental ingestion exposure when handled using appropriate controls. I gave them examples they see every week — broken pressurized water supply lines, tub or sink overflows with no added contaminants, appliance failures involving the supply line, rainwater entering directly without contacting contamination and toilet tank breaks and bowl overflows that contain only clean water without added waste or chemicals. In this kitchen loss, the water came from a cold-water supply line under the sink. That is a textbook Category 1 source. It does not instantly become Category 3 just because it splashed on a cabinet toe-kick or because the contractor does not feel like drinking it. 

At the same time, I didn’t want them to think Category 1 stays clean forever. As we traced the migration across the floor, I reminded them that Category 1 does not stay Category 1 forever. The standard states clearly that Category 1 water can deteriorate. Category 1 water that flows into a clean, uncontaminated space does not immediately change category. However, if that same water flows into an area that is already contaminated, such as a crawlspace with feces and animal activity, a mechanical room with oily residues or a bathroom with visible contamination, the category can change immediately because the water has now contacted unsanitary materials. As time and temperature increase, surfaces and dust get wet, microorganisms begin to multiply and the category can shift higher. Odors, visible growth and obvious soil loading are all signs that water which started clean has deteriorated. 

Watching the crew inspect the affected area, I tried to give them a simple mindset they could use on every job. A good field mindset is to ask the right questions: 

• What was the actual source? 
• What surfaces and cavities did the water contact as it travelled? 
• How long has it been wet and at what approximate temperature? 
• Are there visible contaminants like feces, heavy soiling, organic waste or oily residues? 
• Are there conditions that clearly rise above what would be considered normal for an indoor environment? 

Those answers drive the category determination, not individual comfort levels about drinking it.

To drive the point home, I used examples from everyday life. I asked them if they would drink from a toilet tank. Almost nobody would, yet the tank is filled from the same potable supply as the kitchen sink. That water is still Category 1 at the source until it contacts contamination in the bowl or drain line. The same applies to shower heads and laundry supply lines; they are fed by potable water, but no one fills their water bottle from them. The fact that someone is uncomfortable drinking from a fixture says nothing about the ANSI/IICRC S500 category of the water. On the other side, some people would drink swimming pool water, but that water contains chemicals and potential contaminants and is not classified just because a few people are willing to sip it. The willingness of a person to drink from a source is subjective and highly variable, so it is not a reliable or professional classification tool.  

One of the project managers asked, “What about testing? When do we need a lab to tell us the category?” That opened the door to another important lesson. For technicians and project managers, it is also important to understand where lab testing fits. If someone insists that Category 1 water from a clean supply line has become Category 3 at the moment of discovery, they should be able to justify that position. That justification normally comes from either clear visual evidence of gross contamination, such as sewage, rising groundwater, heavily contaminated soil, organic sludge or from sampling and laboratory results that confirm contamination far beyond what is typical indoors. Most jobs will never require lab work, and that is acceptable. The standard is written so restorers can make responsible, defensible decisions in the field without sending every sample to a lab. However, if no sampling is being done, then the only appropriate way to classify is to follow the ANSI/IICRC S500 logic on source, contact, time and temperature instead of guessing based on “I wouldn’t drink that.”  

By the time we finished walking the job, we had essentially built a repeatable process they could take to the next site. In day-to-day field practice, a practical process looks like this. Start with the source. If the water is from a known sanitary supply and the affected area is otherwise clean, the loss begins as Category 1. Walk the path of the water. Trace where it went, which materials it touched, and whether it entered areas like crawlspaces, unfinished utility rooms or obviously contaminated spaces. Check the clock and the climate. A fresh break discovered within a few hours in a conditioned home is not the same as water sitting for several days in a hot, closed-up structure. Pay attention to conditions such as musty odors, visible microbial growth or heavy soil that indicates deterioration. Finally, document everything. Good photos, written notes describing contamination, odors, pre-existing dirt or growth and temperature conditions are all part of a defensible file.  

Before I left, I told the project manager that when they decide water has deteriorated to Category 2 or Category 3, they need to explain why in writing. They should reference the source, what the water contacted and the time and temperature factors, rather than simply stating that they or the client would not drink it. This helps their documentation stand up to review from insurers, TPA’s and consultants and it also helps their own team understand the reasoning and apply it consistently on future losses.  

Driving away from the site, I thought about how often that same scene plays out on different projects: someone looks at a puddle, shrugs and says, “I wouldn’t drink that,” and the category jumps without any reference to the standard. When technicians and project managers stop relying on the “drink test” and start consistently using the standard, scopes become more consistent, PPE and engineering controls are better matched to the actual risk and the company’s credibility as a professional restoration firm increases. Whether you are dealing with a clean kitchen supply-line break or a severe sewage backup, categorizing water based on source, contact, time, temperature and contamination is what keeps the work aligned with the ANSI/IICRC S500 and protects both workers and building occupants.