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| Method 2: Shock chlorination
of piping systems using a high-pressure metering pump without draining
the piping first: |
| 1. |
Shut off the main line coming in to the house. Identify
an outside hose bib or other opening in the incoming piping. If no
hose bib or opening exists, install a ½” threaded opening
into the main line to use for injecting the chlorine solution. |
| Figure
1: Typical metering pumps with adjustable speed and pump stroke
adjusting knobs. These adjusting knobs make it easy to meter in 10%
to 100% of pump output and adjust output of pump for various applications. |
 |
| 2. |
Hook up a 24 gallon per day output metering
pump to the line, using a injection check valve so the water cannot
back-feed into the metering pump. See Figure 2. If metering pump has
a different output, adjust speed of pump or solution strength. In
this procedure, a concentrated chlorine residual will be injected
while the pipes are under line pressure from the street or city-water
system, so a check valve is used on the piping, to prevent the water
from backing up into the metering pump. Make sure to use a metering
pump that can develop pressures higher than the line pressure you
are injecting into. |
| 3. |
Determine flow rate. Open up the faucets hot and
cold and read the water meter to determine gallons per minute. |
| 4. |
Use the formula and example below to adjust the metering pump: |
| (OR you can use our Online Metering
Pump Selector Calculator on this
page) |
| Example: Compute
metering pump setting to achieve 100 ppm applied chlorine dosage in
a water stream flowing at 5 gallons per minute, using full strength
household bleach: |
| 5 gpm x 100 ppm x 1440 (minutes/day) |
 |
| 52,500 (ppm of laundry bleach) |
|
= |
13.7 gallons per day |
| Output of pump is 24 gallons per day. The example above
calls for 13.7 gallons a day output. |
| 13.7 gallons per day |
|
| 24.0 gallons per day |
|
= |
.57 or 57% Set metering pump speed to 57%, which is 13.7 gal/day |
| 5. |
Run the water in the house or piping until
the bleach solution has filled all the pipes and a strong odor of
chlorine is coming from the fixtures or faucets, both hot and cold.
If possible, test the water at each fixture to verify that there is
at least a 50 ppm chlorine residual, using a DPD method test kit.
|
| 6. |
Allow the water to sit for 12 hours. Retest
for chlorine residual. If the water contains less than 10 ppm of chlorine,
repeat entire procedure. The slime, scale, and odor-producing bacteria
will interact with the chlorine and reduce the amount of chlorine
residual in the piping. If it uses up all the chlorine, or the chlorine
residual is less than 10 ppm, then the procedure may need to be repeated. |
| 7. |
Flush the piping and fixtures well to flush
out scale and colored from water from the piping. Unscrew aerators
and fixtures to avoid these items becoming plugged with sediment that
may have been loosened in the chlorination process. |
| If the Odor Returns: |
| After this procedure is completed,
the odor will be eliminated. If it returns within a few weeks, then
the chlorination procedure can be repeated. However, in many cases
the cold water will still have problems with recurring odors due to
continued presence of sulfate bacteria and low chlorine residuals
in the water. At this point all one can do is to replace the iron
piping with copper. |
| Caution:
this will often loosen up scale, iron deposits and other materials
in the piping, which can clog fixtures, appliances and valves in the
piping system, causing a lot of problems. Care should be taken when
flushing the piping, and all aerators removed to prevent clogging.
In some extreme cases of corroded piping, the piping could fail and
start to leak after this procedure. |
| If you are on septic tank: |
| In most cases, it won’t harm the septic tank
to flush 50 to 100 ppm of chlorine residual into it, on a one-time
basis, with the water from a household piping system. You can also
restart the septic tank bacteria with a septic tank bacterial starter
kit available from the hardware store. |
| Figure 2: Typical
metering pump and solution tank installation showing injection valve
in piping, using a LMI brand metering pump. |
 |
| 3. Odors
in Water Heaters and Hot Water Pipes Only |
| If the cold water does not contain odors, but the hot
water does, then a thorough sanitizing of the water heater tank will
eliminate the odor. See the procedure below.
***If you are not familiar with the functions of your water heater,
DO NOT ATTEMPT this yourself. You can have this done by a licensed
plumber to avoid damage to your water heater, or causing electrical
problems, or gas explosions by improperly restarting the water heater.
Note: If the water heater is old and corroded, cleaning the sediment
from the water and sanitizing by chlorination could cause the water
heater to leak.*** |
| Procedure for Chlorination of
Hot Water Heaters to Eliminate Odors |
| 1. |
Turn off the manual switch if the water
heater is electric. For gas heaters, turn the control to Pilot. Make
sure the pilot is still lit so you can restart the water heater when
the procedure is completed. |
| 2. |
Close the cold-water inlet valve at the water heater. |
| 3. |
Open a nearby hot water faucet and the
T&P (temperature and pressure valve, located on the top of the
water heater) valve to relieve tank pressure. Note of caution: T&P
valves may need replacing if defective or old. |
| 4. |
Drain the water of enough water to compensate
for the bleach to be added. Use a hose connected to the drain valve
if an open drain is not adjacent to the water heater. Tip: have on
hand a hose bib cap, available at any hardware store. When the procedure
is completed, in some cases the drain valve will leak, and a hose
bib cap can be screwed on the end of the drain valve, preventing the
need for a drain valve replacement. Or replace the valve if desired
with a new drain valve. |
| 5. |
Remove T&P valve, anode rod, or disconnect
the hot water outlet pipe from the water heater. |
| 6. |
For best results and to preserve the life
of your water heater, inspect the anode rod. If corroded, replace
with a new aluminum/zinc anode rod, which will create fewer odors. |
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