GWUDI monitoring can save your system money!
During a sanitary survey, the inspector may identify your groundwater source as potentially being ground water under the direct influence of surface water, also known as GWUDI. This is based on well and screening depth, aquifer material, distance to surface water and pumping rates. After the survey, you may receive a letter instructing you to conduct performance monitoring from April to October, and determine if your groundwater source is GWUDI.Monitoring parameters
- Conductivity and temperature are conducted two days a week, which requires a conductivity/temperature meter. The monitoring compares the conductivity and temperature between the groundwater and surface water nearby. This determines if the groundwater is influenced by the surface water source.
- Total Coliform samples are collected monthly at the groundwater source.
- Microscopic Particulate Analysis (MPA) is required three times between April-October on the groundwater source. One in April or May, one in June or July, and one in August or September.
- Aerobic Spores are collected at the same time as the MPA from the groundwater source and nearby surface water.
Results from these monitoring activities will determine if the groundwater source is GWUDI. If systems choose to forgo monitoring, their source(s) will be reclassified as GWUDI. Performance monitoring can cost around $2,000. The department has a limited number of conductivity/temperature meters to loan out, helping offset performance monitoring costs by about $400-$500.
If reclassified, the system will have 18 months to upgrade its system with a filter system, and will be required to increase its chlorine residual to 2.0 mg/l within 60 days until department approved filtration is in place. Once the system updates are completed and online, the monitoring will be increased to meet the surface water requirements. These additional costs could exceed $20,000.
GWUDI training is available when you submit the training request form on our website. Hands-on training will provide the system with information on how to collect representative samples, sample techniques, and how to record the monitoring data. Training units (TUs) in water treatment will be provided to individuals completing GWUDI training. These units can be applied as part of the continuing education hours as required by Regulation 100.
➽ Mike Bacon, local assistance coach
