Several different measurements may be used to determine the amount of lead in water. The most common unit of measurement is micrograms per liter (µg/L), which is the same as parts per billion. Another measurement is milligrams per liter (mg/L), which is the same as parts per million.

According to the Environmental Protection Agency (EPA), hazardous waste is generally classified into four main categories:

1. Characteristic Wastes: These exhibit at least one of four hazardous traits: ignitability (flammable, like gasoline), corrosivity (can rust or decompose materials, like car batteries), reactivity (unstable and can explode, like aerosol cans), or toxicity (harmful when ingested, like lead-based paint).

2. Listed Wastes: These are specific wastes from manufacturing and industrial processes that the EPA has officially designated as hazardous. They include byproducts from processes that use solvents, pesticides, and other chemicals.

3. Universal Wastes: These are commonly generated hazardous items that are subject to streamlined regulations. Examples include batteries, pesticides, mercury-containing equipment (e.g., bulbs), and some lamps.

4. Mixed Wastes: This category includes waste that contains both hazardous and radioactive components, making it subject to regulation by both the EPA and the Nuclear Regulatory Commission.

DIY lead testing kits are available, but they often lack the accuracy and reliability of professional services. Professional testing is recommended for more accurate results, as properly certified testers can provide a thorough analysis, clear recommendations, and the necessary legal documentation if remediation is required.

Lead testing prior to purchasing a property ensures that the new owners are informed about potential hazards, prevents health risks associated with lead poisoning, and facilitates timely remediation.