Are Your Plastic Storage Containers Leaching into Your Water?

Plastics numbered 1 (PET), 2 (HDPE) and 5 (PP) are considered food-safe for cold water storage. Plastics 3, 6 and 7 should be avoided, particularly at high temperatures.

The Plastic Resin Code System

The recycling symbols on the base of plastic containers, numbers 1 through 7, identify the type of resin used in manufacture. These codes matter for water safety because different resins have different chemical stability profiles and leach different compounds under different conditions.

The Temperature Factor

Even food-safe plastics become more problematic at high temperatures. A PET bottle left in a vehicle in Nairobi's sun, where interior temperatures can exceed 60°C, can leach acetaldehyde, phthalates and antimony into the water it contains. Studies show that leaching rates increase exponentially with temperature: antimony concentrations in PET water bottles stored at 60°C for two weeks were 630 times higher than in bottles stored at 25°C.

Source: Antimony and BPA leaching from PET bottles at elevated temperature, Green Matters.

Reusing Plastic Water Bottles

Single-use PET water bottles (resin code 1) are not designed to be refilled repeatedly. The surface develops microscratches that harbour bacteria, and repeated washing, especially with hot water or dishwasher cycles, accelerates chemical breakdown and leaching. Independent tests have found that repeatedly refilled PET bottles can contain bacteria counts exceeding those found in toilet water.

Source: Bacterial contamination in reused single-use bottles, NKY Tribune.

Safe Storage Recommendations

• Use food-grade HDPE (code 2) or PP (code 5) containers for household water storage.
• Store water containers out of direct sunlight and away from heat sources.
• Replace any container that is cracked, heavily scratched or discoloured.
• Never use containers that previously held non-food substances, traces of original contents can leach into stored water.
• Treat water before storage as well as at point of use for a double layer of protection.

Q: Should I worry about the pipes in my house?

A: PVC and CPVC pipes used in Kenyan plumbing are generally food-grade. The primary concern is older buildings that may have copper or lead solder joints, covered in a separate article on new plumbing.

Store clean water in a safe system

iClear's certified components ensure your water stays clean from the membrane to the tap. Find out more.