City of St. Helens Water System Data

Drinking Water System & Filtration Facility Data

Distribution System Data

City of St. Helens Public Water System ID 4100724
City of St. Helens Resident Population Served 12,895 Residents
Size of Distribution system 64 Miles
City of St. Helens Service Connections 4,700 Connections
Total Population Served 12,895 Residents

St. Helens Water Filtration Facility Data

Water Source Groundwater supplied through a Ranney collection system drilled under the Columbia Riverbed strata
Depth of Wells 70 – 90 feet
Water Treatment Plant  Design & Flow Capacity 6 Million Gallons per Day or 4,200 gallons per minute. 113,000 gallons raw water tank and 455,000 gallon finished water reservoir
Plant Type PALL Microza Hollow Fiber Microfiltration membrane separations system
Plant Process Pre Chlorination of Raw water using Sodium Hypochlorite, then filtered through hollow fiber membranes
Post Treatment 3 to 4 hours detention time for thorough disinfection followed with pH adjustment with Sodium Hydroxide
Reservoir Storage 1- 2.5 million gallon reservoir, 1 – 2.0 million gallon reservoir, 1 – 500,000 gallon reservoir and 1 – 200,000 gallon reservoir. 5,200,000 gallons total storage
pH adjustment 25% Sodium Hydroxide (Caustic Soda – NaOH)
12.5% Sodium Hypochlorite (Bleach – NaOCl) 

Raw Water Quality (Before filtration process)

Temperature 12 – 15 Celsius or 53 – 59 degrees Fahrenheit.
Giardia Lamblia Non detect
Cryptosporidium Non detect
Coliform bacteria present (not Escherichia coli from fecal contamination)
*PPCP’s – Pharmaceuticals and Personal Care Products *Atrazine 4.0 ppt and *Sulfamethoxazole 2.1 ppt
Iron .005 – 0.02 mg/l
Copper Non detect
Lead Non detect
Hardness 76 mg/l as CaCO3


 6.7 -7.0

0.00 mg/l (Not naturally occurring)

Filtered Water Quality

Fluoride (Not Added) 0.00 mg/l
Giardia Lamblia Non detect
Cryptosporidium Non detect
Coliform bacteria (not Escherichia coli from fecal contamination) Non detect
*PPCP’s – Pharmaceuticals and Personal Care Products *Atrazine 2.7 ppt and *Sulfamethoxazole – non detect
Iron 0.01 mg/l
Manganese 0.0 mg/l
Sodium 126.0 mg/l  (MCL 250 mg/l) naturally occurring
Hardness 76 mg/l as CaCo3 – this is considered to be a soft water
pH 7.2 – 7.4
Turbidity .01 – .04 NTU (MCL = 0.3 NTU)
Free Chlorine Residual 0.50 – 0.80 mg/l
Sulfate 7.0 mg/l MCL (action level = 250.0 mg/l
Benzene less than 0.002 ppb or ug/l (below detection limit)
Total tri-halomethane (TTHM) chlorine and organics combining  44 ug/l or ppb
Lead (comes from plumbing and faucet fixtures not in Raw water) 3 ppb (action limit = 15.5 ppb)
Copper (comes from plumbing and faucet fixtures not in Raw water) 0.68 mg/l (action limit = 1.3 mg/l)
Total Dissolved Solids 103 mg/l
Nitrate 1.5 mg/l  MCL (action limit = 10 mg/l)


  • mg/l  = Milligrams per liter, same as parts per million
  • ppb = parts per billion , also expressed as Micrograms per liter (ug/l) 1,000 times smaller than a part per million
  • ppt     = parts per trillion, also expressed a nanograms per liter (ng/l) 10,000 times smaller than a mg/l
  • MCL   = Maximum contaminant level
  • TTHM = Total Trihalomethanes
  • NTU = Nephelometric turbidity units – an analysis method used to view and inspect the clarity of water.  MCL = 0.3 
  • *Atrazine – a drug used for the treatment of malaria, conjunctivitis, toxoplasmosis and urinary tract infections
  • *Sulfamethoxazole – a drug used for the treatment of malaria, conjunctivitis (pink eye), toxoplasmosis and urinary tract infections (yeast infections)