Tap Water Vs. Purified Water for Plants

Both tap water and purified water can be used to water most plants

Tap water and purified water are both commonly used to water houseplants, and most of the time both are adequate water sources. But in some situations, one or the other might do more harm than good.

Hardness

According to Texas A&M University Extension housing specialist Susan M. Quiring, tap water is usually safe for most plants. Minerals found in tap water are typically harmless to plants, and processes to remove those minerals, or "soften" tap water, can actually harm plants, as they add dangerous amounts of salt to the water.

Chemicals

In some areas, chemicals in tap water can be damaging to houseplants. Plants should be watered with purified or bottled water, provided that it has not been softened, according to Dawn Pettinelli, Manager of the Soil Nutrient Analysis Laboratory at the University of Connecticut's Agriculture and Natural Resources department.

Considerations

Neither Pettinelli nor Quiring suggest that purified or bottled water is better than tap water that is free of chemicals or softeners. If your local tap water isn't harming the plants by turning leaf tips or margins brown, there there is probably no reason to switch to purified water.

References

• University of Connecticut College of Agriculture and Natural Resources: Watering Houseplants
• Texas A&M University Extension: Hard Water - To Soften or Not To Soften

Resources

• Plant Care: Plan Watering - Thorough is Good!