Water Quality: Update for the Glenmore Community

From Albemarle County Service Authority

Since our last update on February 19, the ACSA, working with our consultant, and the Rivanna Water and Sewer Authority (RWSA) who provides the treated water, have made major progress in the identification, and the source, of the mineral sediment experienced by fewer than 30 residents. The x-ray diffraction laboratory analysis of a second sediment sample confirmed the report on the first sample. The material is composed primarily of calcium phosphate, otherwise known as apatite. In most instances, fluoride is a component of the mineral such that it can more accurately be referred to as fluorapatite. This is a naturally-occurring mineral, and we wish to repeat our assurance to you that the water remains completely safe to drink and use. 

As additional information and test data became available to us, it is now quite clear that the mineral sediment is not coming into customer homes from our pipes in the road. Rather, the sediment is forming within the water heaters of a relatively few homes. Major pieces of evidence for this conclusion include the following:

• The sediment is only found in the hot water. If it was coming from our pipes in the road, it would be found in the cold water, including toilet tanks and outdoor spigots.
• The earlier unidirectional flushing project, while necessary and quite successful in scouring the pipes, did not resolve this issue.
• Some 5-6 customers who have experienced the sediment have had whole-house filters, in some cases for a few, or even several, years, and still had the material inside their home.
• The sediment has now been observed on the elements of electric water heaters of two homes.
• Our consultant has had some limited success in forming this sediment in their test lab using Glenmore water, adjusting the pH of the water, and applying heat.

There is a major focus right now on the pH of the water being a key factor in sediment formation. We have known for years that the pH of the water in Glenmore is somewhat more alkaline than when it leaves the RWSA South Rivanna treatment plant. This is because the water travels through ductile iron pipe with an inner coating of cement-mortar. Due to the long path of the water to your community, it is quite normal for the pH to rise (i.e., the water becomes somewhat more alkaline). During 2022, and especially in the fall, the pH became a bit more alkaline. This is not a health issue at all but is very likely the reason for the sediment to form inside some water heaters.



• There has been no correlation between sediment formation and the type of water heater. It has been found in homes with electric heaters, gas heaters, and tankless (on-demand) heaters.
• Another factor is that total water usage in Glenmore from the mid-fall to mid-spring is some 50% of the usage in the summer. In the cooler months, water usage naturally drops, there is no irrigation occurring, and some residents are away. This is when the pH of the water gets slightly more alkaline. We have had success in the past 4-6 weeks with lowering the pH by flushing some extra water until irrigation usage begins in earnest soon.

Additional testing from Pantops to Glenmore, and within the community, continues. We wish to assure you that we are committed to bringing about a permanent “fix” to this issue.

We apologize again for the inconvenience this has brought to certain customers. I personally wish to thank everyone with whom I have spoken and visited for your understanding and patience during this difficult time.

Tim Brown

Environmental Compliance Specialist

Albemarle County Service Authority

phone: 434-977-4511x119

email:  tbrown@serviceauthority.org