University of Wisconsin Hospital and Clinics
TITLE: Monitoring of the Reverse
Osmosis (RO) Water Systems
Departmental Policy #2.0
Last Revised: October 2016
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Nurse Manager: Joan Watson, MS, RN
Director: Ann Malec, DNP, RN, NEA-BC
Medical Director: Alex Yevzlin, MD
To ensure that all reverse osmosis (RO) water treatment systems used for preparing dialysate
have safe levels of chlorine and chloramines (0.1 mg/L of chloramines) and are functioning
within safe operating parameters. The limits are defined by the Association for the
Advancement of Medical Instrumentation (AAMI).
A. Monitoring of the In-center RO water treatment systems will be done daily.
B. In-center unit testing for free chlorine/chloramines and monitoring of DI tank resistivity
will be performed before each patient shift.
C. Portable RO water treatment systems will be tested prior to each use.
D. Any value outside the normal operating values provided on the attached log sheets should
be reported to Dialysis Solutions at 1-414-550-4622 for corrective action and further
III. GENERAL INFORMATION
A. The water is the In-center Unit is treated on site with softener, activated carbon tanks,
reverse osmosis (RO) deionizers, ultraviolet light and submicron filter. Attachment A:
UWHC Inpatient Dialysis Main Water System Log Sheet includes safe operating
parameters for individual components of the system that are to be checked daily.
Attachment B: Chloramine Test and DI Check Log Sheet, includes safe operating
parameters for chloramine, the primary DI and Polisher DI components that are check for
each patient shift.
B. Water hardness is described as hardness is described as the total concentration of calcium
and magnesium expressed as mg/L or grains/gallon of calcium carbonate. In dialysis,
softening is a pretreatment process for water which will undergo further purification,
such as reverse osmosis (RO). Scale deposits arising from the use of “hard” water can
damage RO membranes.
C. The portable RO water treatment system consists of one particulate filter, two activated
carbon filters and the Gambro WRO300 portable RO system.. Attachment C: UWHC
Daily Acute RO Operation Log includes safe parameters for the feed water, product
water, % rejection and gauge reading pre and post Carbon filter and chloramine level to
be checked prior to each patient treatment.
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D. Chlorine in dialysis water usually consists of free chlorine and chloramines that are
formed during water purification at the water treatment plant. The amine compounds
may be from the impurity of source water, from ammonia added to the water along with
chlorine during water disinfection or from breaking down of urea to ammonia. Although
monochloramine is the main chloramine of concern due to its toxicity, removal of all
chlorine from dialysis water is essential for safe and effective operation of the dialysis
system. The Madison city water supply is treated with chlorine gas at maximal residual
levels of 0.10 to 0.12 parts per million (ppm). Chlorine and chloramines testing must be
done on site because chlorine is a volatile compound which rapidly dissipates.
E. UWHC employees are tested for color blindness upon hire and the Dialysis Department
will obtain proof of testing from employee health proof and note any restriction.
A. Water hardness test strip
B. RPC Ultra Low total Chlorine test strips.
C. Clean sample cup (100 mL)
D. Water System Log
A. Water Hardness Test - performed on the In-center (main) RO water treatment system at
the end of the day or as near the end of day as possible.
Special Considerations for test strips:
o Only staff that has passed a color blindness test may perform this procedure.
o Keep vial tightly capped at all times. Strips are light sensitive.
o Store strips at room temperature, away from heat
1. Open Sample Valve 2 and flush with 1 liter of water.
2. Collect water sample in a clean sample cup, approx. 30ml sample.
3. Remove test strip from bottle and replace cap immediately.
4. Dip Method: Immerse the indicator pad into the sample for 1 second and remove
5. Wait 10 seconds then compare the color of the indicator pad to the color chart on the
bottle. Hardness results should not exceed 1.0 gpg (grains per gallon) or 17.2 ppm
(parts per million).
B. Chlorine/Chloramine Test - performed on the In-center (main) and portable RO water
treatment systems Allow RO to run for at least 15 minutes prior to testing.
Special Considerations for test strips:
o Do not touch indicator pad
o Store strips at room temperature, away from heat at temperatures between
(59°-86° F). Do not refrigerate strips
o Do not use if test strip comes in contact with water before use
o Expiration date and lot number are printed on each foil wrapper.
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1. Open Sample Valve (SV) 1 and flush with 1 liter of water.
2. Rinse clean sample cup with water to be tested, collect a 100 mL water sample.
a. Be sure to collect sample just prior to performing the test as Chlorine tends to
volatilize out of the sample quickly.
3. Remove one test strip from the foil package and dip it in the sample for specified
number of seconds (see below). While dipping the strip move it back and forth at a
constant gentle rate of approximately 1-2 inch wide strokes (forward and backward)
a. If water temperature is ( > 72° F or 22° C) dip time = 20 seconds
b. If water temperature is (64° - 72° F or 17° - 22° C) dip time = 30 seconds
c. If water temperature is (52° - 64° F or 11° - 17° C) dip time = 45 seconds
d. If water temperature is (42° - 52° F or 5° - 11° C) dip time = 60 seconds
4. Remove the strip and shake once, briskly to remove excess water.
5. Wait 20 seconds for the stip color to develop. While waiting fold the white plastic
handle of the test under the reagent area so that it will provide a consistent viewing
background. Alternatively, the reagent strip can be placed on a white surface when
comparing to the color chart.
6. After the 20 second waiting period, compare the test strip to the color chart
immediately to determine the Total Chlorine level.
Sample Color chart. Use color chart on container for comparison.
7. Test Results must be less than 0.1 ppm (parts per million). If test results from SV# 1
are greater than 0.1 ppm draw sample from SV # 2 and refer to Policy 2.2 Reverse
Osmosis (RO) In-center Loop Contingency Plan.
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1. RO system being tested must be up and running for 15 minutes prior to
recording any values on the RO water system log sheets.
2. Use the UWHC Inpatient Dialysis Main Water System Log Sheet and
corresponding RO system TAG (placed throughout the hemodialysis water room
by Dialysis Solutions) to locate and obtain gauge readings. Record the readings
obtained in the corresponding row on the log sheet. Normal operating parameters
are located on the left.
3. Record test results obtained for water hardness on the UWHC Inpatient Dialysis
Main Water System Log Sheet. Note these readings are to be obtained at the end
of the day. Normal operating parameters are located on the left.
4. Record test results obtained for chloramine and DI resistivity on the Chloramine
Test and DI Check Log Sheet as indicated for each shift. Normal operating
parameters are located on the left.
5. Record test results and readings obtained for the portable RO water system on the
UWHC Portable WRO300 Operation Log Sheet as indicated before each patient
treatment. Normal operating parameters are located at the top of each column.
6. Any value outside the normal operating values provided on the log sheet should
be reported to Dialysis Solutions at 1-414-550-4622 for corrective action and
o Association for the Advancements of Medical Instrumentation (AAMI), Water
Treatment Equipment for Hemodialysis Applications, ANSI/AAMI RD62:2006
o Centers for Medicare and Medicaid Services. Conditions for Coverage for End-
Stage Renal Disease Facilities Interpretive Guidance, 2008.
o Attachment A: UWHC Inpatient Dialysis Main Water System Log Sheet
o Attachment B: Chloramine Test and DI Check Log Sheet
o Attachment C: UWHC Portable WRO300 Operation Log Sheet
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