Sodium in Drinking Water

Sodium is a naturally occurring element that is widely distributed throughout the Earth’s rocks and soils, most often found in combination with chloride in the form of salt (sodium chloride). The presence of sodium in groundwater can result from a number of sources including the weathering of minerals in the soil, salt-bearing geological formations, deposition of salt spray, the use of salt for road de-icing, and in coastal areas, intrusion of salty ocean water into fresh groundwater sources. In PEI, sodium levels in groundwater are relatively usually fairly low, but can become elevated in areas near the coast, or in areas of heavy salting of roads. 

What are the health concerns?

Sodium is considered to be an essential nutrient for human health and the main source of sodium is from foods, with drinking water making up only a small portion of normal dietary intake. There is no health based drinking water guideline for sodium however the Guidelines for Canadian Drinking Water Quality recommend sodium levels do not exceed 200 mg/L, based on the presence of a salty taste at concentrations above this level, and for the general population, this level is considered protective of human health. Nonetheless, for individuals on a sodium restricted diet, or who suffer from hyper-tension, they may want to discuss their sodium intake from drinking water with their doctor. 

What are the treatment options?

Elevated sodium levels can sometimes be reduced by reconstruction of your well, or in other cases, by the use of a water treatment device, and it is recommended that advice from a qualified groundwater professional be sought prior to deciding what solution best meets your particular situation. The most common water treatment devices for reducing the sodium content of drinking water are reverse osmosis or distillation treatment systems. 

The Department does not recommend specific brands of treatment devices; however, it is recommended that consumers purchase devises bearing a label that indicates it has been certified to NSF/ANSI Standard 58 for Reverse Osmosis Drinking Water Treatment Systems or NSF/ANSI Standard 62 for Drinking Water Distillation Systems. 

As with the use of any drinking water treatment device, the effectiveness of treatment should be verified by sampling after installation. In addition, it is important to ensure the device is used and maintained according the manufacturer’s directions and its performance periodically confirmed by sampling.