
For Commercial Applications
ES-WQ-PWS20_S20-2
Job Name 
Job Location 
Engineer 
Approval 
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Series PWS20 and 
Series PWS20-2
Commercial Water Softening 
Systems
Connection Size: 2" (50mm) 
Flow Rates: Up to 105 gpm (397 lpm)
Watts Pure Water Series PWS20 and PWS20-2 water softening 
systems are highly efficient conventional cation exchange type 
water softeners. They are suitable for commercial applications 
ranging from 90,000 to 600,000 grains of hardness removal 
per tank and flow rates up to 105 gallons per minute (397 lpm). 
Where continuous softened water is required PWS20-2 duplex 
alternating systems can be specified for uninterrupted service. 
Regeneration is meter demand initiated. All cycles of regeneration are fully automatic and do not require manual actuation.
Watts Pure Water Series PWS20 and PWS20-2 water softeners are designed for point of use or point of entry applications 
where the benefits of softened water are required. These systems exchange scale-forming calcium and magnesium ions 
with non scale-forming sodium ions to create soft water for a 
variety of applications.
Steam boiler make up water, water heater pretreatment, 
reverse osmosis pretreatment, cooling tower make up water, 
sterilizer make up water, washing, and process water are all 
common applications for the Watts Pure Water Series PWS20 
and PWS20-2 water softeners.
Softened water provides a wide variety of benefits from not 
introducing scale into pipes, valves, water heating equipment, 
heat exchangers, and cooling towers to reducing mineral build 
up in areas that see excessive splashing such as food preparation counters and sink areas. Softened water also conserves 
soaps and cleaning agents by eliminating the formation of soap 
curd, so your cleaners can work on cleaning – not reacting with 
the hardness in your water.
Features
• WQA Certified fully automatic metered demand control valve
• Sophisticated digital electronic controls that store operating 
history that can be accessed by the user
• Fully adjustable regeneration cycles
• Durable brass bodied control valve for years of service
• Dry contact lock out switch for remote interface is standard
• WQA Certified high capacity resin
• Highly corrosion resistant NSF Certified fiberglass tanks
• Durable polypropylene lower distribution system
  Contractor 
  Approval 
  Contractor’s P.O. No. 
  Representative 
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PURE WATER
Series PWS20-2Series PWS20
Specifications
A Watts Pure Water Series PWS20 and PWS20-2 water softening system shall be installed on the building’s main water 
line just after it enters the building. The installation point shall 
be after any backflow prevention or pressure regulating valves. 
Other installation options are to install a system just before 
the water heater or other types of equipment needing the 
protection of softened water. In installations where dedicated 
cold water make up to a water heater is the installation point, 
a backflow preventer and a thermal expansion tank must be 
installed as well. The system shall be installed with a bypass 
valve to allow for the shut down and removal of the unit without interrupting the water supply to the building.
The water softener shall be a down flow regenerated, metered 
demand, sodium cycle cation exchange type system with all 
components necessary for proper operation. Electrical requirements are 120 volt 60 hertz. A local drain is required to accept 
drain water from the system. The feed water pressure must not 
fall below 25psi or exceed 125psi. Water temperature must not 
fall below 34°F or exceed 110°F (1°C - 43°C).
The system shall provide softened water measuring less than 
one grain per gallon of hardness as Calcium Carbonate when 
operated within the manufacturer’s operational specifications.
Standards
Control Valve- WQA Certified to NSF/ANSI Std. 61 
Ion Exchange Resin- WQA Certified to NSF/ANSI Std. 44 
Mineral Tank- NSF Certified to ANSI Std. 44 or 61
Watts product specifications in U.S. customary units and metric are approximate and are provided for reference only. For precise measurements, 
please contact Watts Technical Service. Watts reserves the right to change or modify product design, construction, specifications, or materials without prior notice and without incurring any obligation to make such changes and modifications on Watts products previously or subsequently sold.
 

Feed Water Guidelines
pH  ........................ 6 to 10
Hardness (maximum) .......... Depends on customers acceptable
   hardness leakage level.
Water Pressure .............. 25psi to 125psi (171kPa to 8.5 bar)
Temperature .................  34 - 110°F (1 - 43°C)
Free Chlorine (maximum) ....... 1mg/L
Iron (maximum) ............... 1mg/L
Oil and H2S  ................. None Allowed
Turbidity  ................... Less than 5.0 NTU
For all other guideline information please contact your Watts  
representative.
Dimensions - Weights
Note: Do not use with water that is microbiologically unsafe or 
of unknown quality without adequate disinfection before or after 
the system. 
PWS20
E
E
F
F
C
C
G
G
FRONT
D
D
B A
B
SIDE
C
A
E
F
FRONT
PWS20-2
D
B
G
SIDE
Series PWS20
 MODEl NO.  DIMENSIONS  WEIGHTS
  A  B  C D E F G
    in. mm in. mm in. mm in. mm in. mm in. mm in. mm lbs. kgs.
 PWS20131D11 673/8 1711 673/8 1711 777/8 1978 16 406 211/4 538 18 457 40 1016 265 120 
 PWS20131E11 67 
 PWS20131F11 68 
 PWS20131G11 70 
 PWS20131H11 76 
 PWS20131I11 80 
 PWS20131J11  86  2184  86  2184  96
3
/4 1721 673/4 1721 771/8 1959 17 432 221/4 564 18 457 40 1016 350 159
1
/2 1740 681/2 1740 7815/16 2004 181/8 460 231/4 589 24 607 41 1041 400 182
1
/2 1791 701/2 1791 8015/16 2055 211/8 536 2411/16 627  24 607 50 1270 600 273
3
/4 1949 763/4 1949 871/8 2213 241/8 613 261/4 665 30 762 50 1270 710 323
1
/4 2038 801/4 2038 905/8 2302 301/8 765 301/8 764 39 991 48 1219 1160 527
7
/16 2449 361/8 917 361/8 917 39 991 60 1524 1560 709
A
Series PWS20-2
 MODEl NO.  DIMENSIONS  WEIGHTS
  A B  C D E F G
     in. mm in. mm in. mm in. mm in. mm in. mm in. mm lbs. kgs.
 PWS20131D21 673/8 1711 673/8 1711 777/8 1978 16 406 60 1524 18 457 40 1016 450 205 
 PWS20131E21 67 
 PWS20131F21 68 
 PWS20131G21 70 
 PWS20131H21 76 
 PWS20131I21 80 
 PWS20131J21 86 2184 86 2184 96
3
/4 1721 673/4 1721 771/8 1959 17 432 60 1524 18 457 40 1016 500 227
1
/2 1740 681/2 1740 7815/16 2004 181/8 460 70 1778 24 610 41 1041 800 364
1
/2 1791 701/2 1791 8015/16 2055 211/8 536 75 1905 24 610 50 1270 1200 545
3
/4 1949 763/4 1949 871/8 2213 241/8 613 87 2210 30 762 50 1270 1400 636
1
/4 2038 801/4 2038 905/8 2302 301/8 765 104 2642 39 991 48 1219 2200 1000
7
/16 2449 361/8 917 115 2921 39 991 60 1524 3000 1364
 

Specifications
    MINERAl TANK  BRINE TANK  SOFTENING  lBS. SAlT PER  FlOW RATE & PRESSURE 
  TANK RESIN GRAVEl TANK SAlT  CAPACITY  REGENERATION  SERV  DROP BKW 
 MODEl NO.  SIZE  Ft
3
  SIZE  FIll  MAX  MIN  MAX  MIN  GPM  PSI  GPM
 PWS20131D11  14" x 65"  3  60 lbs. 18" x 40"  400  90 K  60 K  45  18  25/40  15/25  5 
 PWS20131E11  16" x 65"  4  80 lbs. 18" x 40"  400  120 K  80 K  60  24  35/55  15/25  7 
 PWS20131F11  18" x 65"  5  100 lbs. 24" x 41"  600  150 K  100 K  75  30  57/65  15/25  10 
 PWS20131G11  21" x 62"  7  100 lbs. 24" x 50"  600  210 K  140 K  105  42  60/77  15/25  12 
 PWS20131H11  24" x 72"  10  200 lbs. 30" x 50"  1200  300 K  200 K  150  60  74/97  15/25  15 
 PWS20131I11  30" x 72"  15  400 lbs. 39" x 48"  2200  450 K  300 K  225  90  80/100  15/25  25 
 PWS20131J11  36" x 72"  20  500 lbs. 39" x 48"  2200  600 K  400 K  300  120  84/105  15/25  35
Ordering Information
    SPACE 
 MODEl NO.  DESCRIPTION    REQUIRED   WEIGHT 
         D X W X H  lBS  KGS
 PWS20131D11  3 Cubic Foot 2" Simplex Softener with Flow Meter  18" x 37" x 87"  265  120 
 PWS20131E11  4 Cubic Foot 2" Simplex Softener with Flow Meter  18" x 39" x 87"  350  159 
 PWS20131F11  5 Cubic Foot 2" Simplex Softener with Flow Meter  24" x 48" x 89"  400  182 
 PWS20131G11  7 Cubic Foot 2" Simplex Softener with Flow Meter  24" x 52" x 89"  600  273 
 PWS20131H11  10 Cubic Foot 2" Simplex Softener with Flow Meter  30" x 60" x 96"  710  323 
 PWS20131I11  15 Cubic Foot 2" Simplex Softener with Flow Meter  39" x 75" x 106"  1160  527 
 PWS20131J11  20 Cubic Foot 2" Simplex Softener with Flow Meter  39" x 81" x 107"  1560  709 
 PWS20131D21  3 Cubic Foot 2" Duplex Alternating Softener with Flow Meter  18" x 60" x 87"  450  205 
 PWS20131E21  4 Cubic Foot 2" Duplex Alternating Softener with Flow Meter  18" x 64" x 87"  500  227 
 PWS20131F21  5 Cubic Foot 2" Duplex Alternating Softener with Flow Meter  24" x 72" x 89"  800  364 
 PWS20131G21  7 Cubic Foot 2" Duplex Alternating Softener with Flow Meter  24" x 80" x 89"  1200  545 
 PWS20131H21  10 Cubic Foot 2" Duplex Alternating Softener with Flow Meter  30" x 90" x 96"  1400  636 
 PWS20131I21  15 Cubic Foot 2" Duplex Alternating Softener with Flow Meter  39" x 111" x 106"  2200  1000 
 PWS20131J21  20 Cubic Foot 2" Duplex Alternating Softener with Flow Meter  39" x 123" x 107"  3000  1364
Notes:  Capacities are based on resin manufacturer’s data and are dependent upon influent water TDS, temperature, bed depth, and 
flow rates. Feed water must be free of oil and color. Pipe size, tank size, and space requirements are in inches. Capacities and flow 
rates expressed above are per tank. Flow rates listed at 25psi drops are for intermittent peak flow rates and are not to be used as 
continuous flows.
Note: This information is not intended to replace the product 
installation and safety information available or the experience of 
a trained product installer. Please refer to the product installation and safety instructions for further information.
 

A Watts Water Technologies Company
USA: North Andover, MA • Tel. (800) 224-1299 • www.watts.com 
Canada: Burlington, ON • Tel. (888) 208-8927 • www.wattscanada.ca
ES-WQ-PWS20_S20-2  1136    © 2011 Watts