We thank the fine folks at The Water Quality Association (WQA) for the contents of this document addressing frequently asked questions about lead in drinking water.
How can lead get into the water supply?
Studies indicate nearly all the lead in tap water is a result of corrosion resulting from materials containing lead coming into contact with water after it leaves the treatment plant. Lead can enter a home's drinking water by leaching from lead service connections, from lead solder used in copper piping and from brass fixtures.
What are the potential health effects from lead?
Lead can enter the human body in different ways. Lead poisoning often shows no symptoms, however signs such as irritability, weight loss, vomiting, constipation or stomach pain can occur. The human body can be damaged by ingested lead and the most acute cases of lead poisoning can cause death. Children are at more risk than adults when it comes to the dangers of ingesting lead. Young children and pregnant women are at the greatest risk, even from short-term exposure. Reduced intelligence, impaired hearing and decreased growth are associated with blood levels as low as 10 micrograms of lead per deciliter of blood. Damage to the brain, kidneys and bone marrow can occur with lower exposure. Coma and convulsions can also be associated with lower exposures of lead. Lead can also damage a person's nervous system and red blood cells. Individuals will adsorb more lead if they have poor nutrition than those with better diets.
Where can I go to get my water tested?
Where do I find a product certified for lead reduction?
It is absolutely critical that the product you are searching for has been tested and certified to Standard 53 for Lead Reduction.
Does a 'lead-free' claim mean the product can remove lead from water?
No, a product is considered compliant with the 'lead-free' standard NSF/ANSI 372 if its weighted average lead content is no greater than 0.25%. This claim is about the lead content in the materials that it is made from and is not a claim of product performance.
How do I maintain a filter once it is installed?
Consumers should follow the manufacturer's stated capacity, which is found on the product labelling, brochures and on the nsf website. Pay close attention to product flow rates for lead reduction. A product may be capable of providing a flow rate of 1.0 gallon per minute under normal circumstances but require an intentional flow restriction to only 1/2 gallon per minute for lead.
What treatment methods can be used at the tap or whole house?
Lead can exist in water in a broad array of forms, therefore more than one type of technology may be needed for adequate removal. Soluble (or dissolved) lead may be removed by ion exchange, reverse osmosis, adsorption, or distillation. Insoluble (or particulate) lead may be removed by fine filtration, adsorption, reverse osmosis and distillation.
NSF certified solid block and precoat adsorption filters, using a mixture of activated carbon and a lead adsorbent, can remove particulate lead. Contact time, type and size of adsorbent, flow rate and micron rating are critical to the success of this treatment technology.
NSF certified Reverse Osmosis is effective because the membrane removes the soluble lead and also acts as a barrier to particulate lead. Strong-acid cation exchange water softeners only remove soluble lead but not particulate lead. Properly designed and operated distillation units are capable of reducing both forms of lead.
How do you determine if the lead in my water is particulate, dissolved or a percentage of both?
Field sampling kits for dissolved and total lead can be obtained through a local certified drinking water laboratory, or through the WQA laboratory.