The majority
of private water systems consist of wells drilled into groundwater aquifers.
Springs, cisterns, and ponds are other kinds of private water systems. Wells
and springs tap groundwater. Ponds tap rainwater runoff. Cisterns tap and
capture rainwater.
Generally
speaking, groundwater closest to the surface or in contact with the surface or
surface waters is more likely to be polluted. That is one reason why
groundwater wells are required to be cased to a certain minimum depth, usually
15-25 ft. A distance between surface waters and drinking water aquifers is
desirable in that the water is naturally purified and filtered as it moves
downward through soil and rock, the more filtration and time, the cleaner the
water becomes. There are many examples of surface water contaminating shallow
groundwater.
The graphic below
shows some groundwater geology variations and how aquifers are often tapped.
The next
graphic is a (composite) schematic of a typical private water well.
Well Design and Construction
In many states
well permitting, inspections, and examination and verification of well data
from well logs and well completion reports are done by local and county health
departments with assistance from the state health department and the Dept. of Natural
Resources (DNR). The DNR keeps up the state water well database and stores the
logs and completions as do the health departments.
Wells must be
cased below a certain depth, and the grout or cement used to seal the well off from
adjacent rock must be of a certain concentration in terms of weight per gallon
of water. We had a calculation sheet to determine this. Correct piping, pumps, pressure
tanks, and backflow prevention, are verified in an inspection. Since grout should go
to the surface it can be verified by probing.
Well logs and
completion reports should be accurate and complete. Well logs include formations
encountered, depth of casing(s), casing sizes, where water was encountered, how
much grout and water or cement and water were used in mixing a slurry, and how
the grout or slurry was added to the hole. The logs and completion reports also
act as official state records filed by state permit number. GPS coordinates and
site information, well production pump tests, sustainable yields (in gals/min),
pump make and model, pump setting depth, whether there are screens, shale
baskets, or any other added features of the well, and other pertinent information
are given on these two reports.
Most drilling
in my area is via rotary drilling but there are other types of drilling rigs,
pounded wells, and dug wells, but those last two are becoming less and less
common.
Water Disinfection and Testing
Private water
systems are typically tested for coliform bacteria and E. coli. They may be
also be tested with test strips to screen for the presence of nitrates and
nitrites. Nitrate and nitrites, though rarely present, can indicate groundwater
contact with animal manure or fertilizer. Positive tests are most common in
agricultural areas and levels vary by season. If it is a new well, it is common
to disinfect it with a flush of chlorine and/or vinegar. Following sufficient
contact time with the disinfecting agent, it is considered to be important to then
remove all the chlorine from the system before testing the well for the target
bacteria. This is in order to get the most accurate test results for the presence
of the bacteria. The cutoff for coliform bacteria is 4.2 MPN. The presence of coliform bacteria is not in itself dangerous but its presence makes it more likely that dangerous forms of bacteria will be present as well. Disinfection is
usually done by the well driller after the well is completed. They add chlorine
at a sufficient concentration based on hole size and depth. There is a simple way
to calculate this. Then they flush the system with elevated chlorine levels.
Then the system is flushed for a long period of time. Ideally, it should be
flushed until it is free of chlorine for 24 hours, but this is not always
practical. If the sample comes back too high in coliform bacteria, a deeper
disinfection is done, and the water is re-tested. A deeper disinfection may
include cleaning the walls of the well casing or even digging up water lines and
re-laying them if bacteria in the pipe is suspected.
Coliform bacteria
can access the system in a number of ways including its presence in soil where
soil may have gotten into the well and/or the pipes. It can also form on water
taps. States may require a dedicated sample tap to test the water. This is
usually in the basement on the consumer side of the pressure tank. The water
should be run at least until the pressure tank kicks on so that any stale water
inside can be pumped out. Water sitting in the tank for a long period could
allow bacteria to grow. The tap is disinfected with chlorine at sufficient
concentration, with 70% isopropyl alcohol, or with a flame. The water tester
should also avoid touching the sample lid interior, breathing on the sample,
etc. to avoid contaminating the sample.
It is often
recommended that home well water and other private water systems be tested once
a year or at least once every five years. However, this is often not done at
all. Nowadays, there are home water testing services like Tap Score where you
can order a test kit, take your own water sample, and send it to a lab for
analysis. Otherwise, local health departments can test the water and send it to a
lab for analysis.
Older wells may
be in need of maintenance or may be in need of decommissioning due to
contamination. In some areas steel casing used in older wells may corrode, allowing
metal fragments to enter the water. That could be dangerous. Most wells these
days use plastic casing that does not corrode. According to the Family Handyman
wells are commonly contaminated by:
·
Man-made contaminants from agriculture, mines
and industry;
·
Natural contaminants like arsenic, heavy
metals, fluoride and radioactive substances;
·
Microorganisms, especially if your well is
older or the casing is damaged;
·
Depth, since shallow wells don't naturally
filter water as well;
·
Contaminants from old plumbing, like lead and
copper pipes.
Almost one-fourth of private wells contain
elevated levels of at least one contaminant, according to a U.S. Geological
Survey study. Family Handyman also has a list of contaminants commonly tested for
in sample analysis:
·
Bacteria, including coliform and E. coli
(some health departments also offer free coliform * tests)
·
Nitrate and nitrite, which are often from
agriculture;
·
Heavy metals like lead, arsenic, copper and
total (or hexavalent) chromium;
·
Fluoride, which is unhealthy at higher
levels;
·
General chemistry, including hard water, pH,
alkalinity, total dissolved solids, turbidity, grains per gallon and
conductivity.
If you can afford it, it's also good to test for:
·
Forever chemicals (PFAS), volatile organic
compounds (VOCs) and other industrial wastes;
·
Radioactive particles like radium and
uranium;
·
Pesticides and herbicides.
Water Hardness and Water Softeners
Well water may be
high in dissolved minerals in ionic form such as magnesium and calcium. Magnesium
and calcium can create hard water. These wells may require a water softer to
make the water more palatable and less damaging to systems. Hard water,
although generally safe to drink, can impede the actions of soap, shampoos, and
laundry detergents, and leave deposits and ‘rings’ on cooking equipment and containers.
Hard water can also shorten the lifetime of water heaters and plumbing
fixtures. Some water testing kits test for water hardness. According to Home
Depot:
“A level of 1 grain per gallon (gpg) or higher
technically indicates some water hardness, but 7 gpg often indicates that a
water softener may be needed at your home.”
A water softening system should be chosen based on expected water
use in gallons per day. The most common type of water softener is an ion
exchange system. Home Depot explains how ion exchange water softeners work:
- Water
softeners work by filtering hard water through a mineral tank. The tank
contains a bed of plastic beads or resin beads that have negative
electrical charge. The negative charge of the water softener resin
attracts the positive charge of such “hard” particles as calcium and
magnesium, leaving them on the beads and removing them from the water.
- Over
time, the water softener runs a regeneration cycle to clear the hardness
particles from the beads. The unit’s control valve sends a mixture of salt
and water from the brine tank into the resin bed. The salt attracts the
minerals from the beads, and the excess debris is flushed from the system
and down the drain.
- Regeneration
cycles occur at least once a week, but often more. The frequency of
regeneration cycles depends on numerous factors, including how hard your
water is and how much water you use. The harder the water and the more
water used, the more frequent regeneration cycles will need to be.
Regeneration cycles use about 50 gallons of water on average, but this
will depend on the water softener system. Unless you have a dual-tank
water softener, the equipment cannot be used during the regeneration
cycle.
- Resin
beads usually do not need to be replaced. They can typically last the
entire lifespan of the water softener system, but may need replacing every
10-15 years or so. However, to maintain your water softening
effectiveness, periodically refill the brine tank with water
softener salt.
There are also dual tank systems that keep water available during
regeneration and salt-free systems.
Water Purification Systems That Provide Continuous
Disinfection
Some wells may be
contaminated enough to require water purification systems. If after multiple deep
disinfections, a good water sample cannot be obtained, then the system owner
can opt for a water treatment/purification system. These are also known as continuous
disinfection systems. They may be required for well water, spring water, cistern
water, and water from ponds or streams, and can be used for treated public water as
well. These involve a UV light to kill off bacteria and other microorganisms
and filtration. They work best with clear water since it allows the light
through better. There are Class A and Class B systems. In some situations,
Class A systems may be required to meet state codes for continuous disinfection.
Shown below are how UV disinfection works and the ANSI/NSF 55 Class A and B requirements
for water purification systems. They come from a blog by John Woodard of Fresh
Water Systems.
Springs, Ponds, Cisterns, and other Water Sources
Many people rely
on these unconventional private water sources. We got calls about developing
springs and ponds. The first step there is to get the water tested. Most
springs require some disinfection with chlorine, but ponds may require more
disinfection and have specific requirements regarding their relative position
to runoff. I once relied on water from a cistern that was filled regularly with
public water trucked in. We needed no disinfection system because it was public
water and likely would not have needed it in that state.
Water Well Maintenance
Wells should be visually inspected
from time to time, noting anything broken or breached so that surface water of
soil could contact the water.
“NGWA {National Ground Water Association} recommends
homeowners hire a licensed well contractor to inspect systems every year to
check the pump's capacity/flow, valves, electrical conductance/motor and the
well's water levels. However, WSC {Water Systems Council} recommends only doing
this every five years, as long as there is no concern with the well.”
“If your water pressure has dropped, contractors can also
check for pump wear and mineral buildup inside the pump casing. "Over the
years, this will give insight on water levels, quality and quantity, plus
provide some forward vision as to when you might experience a pump
failure," says Traut.
“If you hear clunking, your well pump runs constantly or
your water pressure becomes low, it could be a sign that there's not enough air
pressure in the tank.”
Replacing a pump in a water well can cost $1000 to $2500
plus labor. Drilling a new water well varies by depth, region, and geology, but
recent costs can be above $20,000. The life of a water well is estimated at 20-50
years. The life of a pressure tank can vary based on water composition and quality,
but the range is 5 to 30 years.
Smart Water Systems
A more recent development
is digitally controlled smart water systems. Smart water systems can detect
leaks and make any water system function optimally.
“A smart water system is a modern and innovative solution
that combines technology and water management to prevent leaks, save money, and
promote water conservation. It typically consists of a network of sensors and
devices that monitor water usage, detect leaks, and allow for remote control
and management. These systems can be installed in both residential and
commercial settings, providing real-time data and insights into water
consumption patterns. By tracking water usage and identifying potential issues such
as leaks or abnormal usage, smart water systems help users take proactive
measures to prevent water wastage, reduce utility bills, and ensure the
efficient use of this precious resource.”
References:
How To
Maintain Your Well Water System. Karuna Eberl. The Family Handyman. January 31,
2024. How To Maintain Your Well Water
System (msn.com)
Homeowner’s
Guide To Well Water Testing. Karuna Eberl. The Family Handyman. February 12,
2024. Homeowner’s Guide To Well Water
Testing (msn.com)
Smart
Water Systems: Preventing Leaks and Saving Money. Jessica Fritsch.
AllTheThings.Best. August 30, 2024. Smart Water Systems: Preventing Leaks
and Saving Money (msn.com)
Certified
laboratory water testing for home and business. Tap Score. Water Test Kits By Certified Laboratories – SimpleLab Tap Score
Types
of Water Softeners. Home Depot. Types
of Water Softeners - The Home Depot
UV
Water Purification Systems: NSF Class A and B. John Woodard. Fresh Water
Systems. August 23, 2018. UV
Water Purification Systems: NSF Class A and B – Fresh Water Systems
Private
Water Wells and Private Water Systems. KnowYourH2O. Private Water Wells and Private Drinking Water Systems, Well
Water, Unregulated
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