Wells and water are necessarily of concern to anyone buying or selling country real estate in West Sonoma County. Without adequate water supply, otherwise excellent pieces of land are unbuildable and therefore worth only a fraction of their what would otherwise be their value. For this reason, well tests, which measure the ability of a well to deliver potable water consistently over a period of time, are normally performed when a property is sold, either prior to the listing by the seller or during the escrow process by the buyer. A well test takes a few hours typically, and provides a good opportunity for any party to the transaction to learn about wells from the testing technician. I gathered the facts below from Ray Carlson, a veteran of the well drilling and testing business in Sebastopol, Occidental and surrounding areas of West Sonoma County.
-For a good all around reference for septic, well and water treatment systems look to the book
“Cottage Water Systems” by Max Burns.
-Well pumps are typically of the submersible type, being more energy efficient and, crucially, capable of delivering water from a depth required by most wells. Modern submersible pumps are 72% efficient. Dual pipe jet pumps, a type of surface pump are by contrast only 35% efficient, since they need to push water down before they can bring it up. Single pipe pumps are limited in depth by the physics of the atmospheric pressure. At sea level, this limit is 28 feet. As a rule of thumb, in Sonoma County, we use 25 feet.
-Bucket wells have the advantage of incorporating storage into the well itself. They are typically cased with concrete rings. Older wells are often of this variety.
-Contemporary wells are typically 9 7/8” holes with 5” pvc casing, back-filled with either gravel or sand. The region of pipe that is within the water bearing zone is perforated. The well driller, by a process known as “reading the cuttings” determines by the look of the drill product and the depth the location of the water bearing zone.
-Certified well tests take between 8 and 12 hours and must show a sustainable delivery rate of 1 gallon per minute per connection, that is, per dwelling unit.
I was surprised when I first began to learn about wells in the vicinity of Sebastopol that dowsing remains a trusted means of finding water. When a well is drilled, a dowser–a person who uses a forked stick, balanced in his or her hands, to detect the presence beneath them of water, is as likely to be employed for the job as a geologist. Sometimes both cooperate to accomplish the task.