Hillcrest Water Quality Issues
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City of Yuba City - Hillcrest Water System

South Walton Area
Ad-Hoc Advisory Committee Council Meeting
 November 29, 2007
Water Quality
Water Quality Monitoring Overview
  • Every water system required to monitor source water, treated water and distribution system
  • DPH regulates what is sampled and frequency of samples to ensure clean, healthy drinking water

1-Depends on type and size of system
 
Hillcrest Water Quality Issues

Arsenic       Nitrates       Iron       Manganese       Hardness
Arsenic

  • Causes
    1-Naturally occurring inorganic contaminant found in groundwater and occasionally in surface water
    2-Sources include agricultural, industrial and mining activities

  • Effects
    1-Toxic in high concentrations
    2-Carcinogen for lifetime exposure
Nitrates

  • Causes
    1-Naturally occurring-small amounts
    2-Agricultural activities (fertilizers)
    3-Septic systems

  • Effects
    1-Methemoglobinemia-blue baby syndrome
    2-Affects infants and some pregnant women
    3-Affect people with immune deficiencies
Iron and Manganese
  • Causes
    1-Natural deposits in the ground

  • Effects
    1-Rusty taste and look to water
    2-Stains clothes
    3-Discolors plumbing fixtures
    4-Promotes growth of iron bacteria
    5-Aesthetics-taste and odor

Water Quality Monitoring
  • Required training and certification
    1-Laboratory is certified by DPH
    2-Lab technicians have 4 year science degrees
    3-All sampling personnel are trained and certified per DPH requitements
  

Hillcrest 2/3 Water Quality

2001--2006 Sample results*
  Arsenic Iron Manganese Nitrate
MCL 10 ppb 300 ppb 50 ppb 10 ppb
  19.9
7.9-39		 26.7
20 - 80		 25.9
20 - 1000		 4.6
N.D. - 11.2

Average hardness--239 ppm / 14.0 grains/gal

*Data taken from annual consumer confidence reports

What Yuba City Has Done
  • February 2005-Pilot plant #3
     
  • October 2005-Pilot testing for arsenic removal at filtration plants using ferric chloride (temporary solution to get into compliance)
     
  • August 2006-Plant 2 filter improvements
  • May 2005-Replaced plant #3
     
  • June 2006-DPH approves use of FeCl3
     
  • November 2006-Cost/benefit analysis
    (ground water versus surface water)

Hillcrest 2/3 Water Quality

2007 Sample results (Nov '06-Oct '07)
  Arsenic Iron Manganese Nitrate
MCL 10 ppb 300 ppb 50 ppb 10 ppb
  7.8
3.3-14		 53
70 - 175		 10.5
10 - 39		 .27
0.06 - 0.48

Average hardness--227 ppm / 13.3 grains/gal

*Data taken from annual consumer confidence reports

Hillcrest Water Quality Summary
  • Arsenic levels have
    decreased
  • Increase in iron levels
  • Filter efficiency has
    decreased

Surface Water Water Quality Issues
  • Disinfection by-products (DBP)
    Total trihalomethanes (TTHM)
    Haloacetic Acids (HAA)
  • Total organic carbon (TOC)
Questions from 2nd Meeting
Q-What are other potential contaminants within existing system?

MTBE    -    PERCHLORATE   -    PCE / TCE   -    UNKNOWN

Q-Where is the murky water coming from?

1-Short periods of time  (treatment plant malfunction)

2-Iron and manganese that settle in the distribution
pipes and gets stirred up under high flow conditions

3-Water softener failing

4-Home plumbing

5-Hardness

 


Q-Nitrates in the groundwater system--What are they now?
Less than 0.5 ppm
Q-How will water be improved?

Remain on groundwater

1-Meet water quality regulations

2-Increased water storage

3-Increase supply to meet demands

4-Ground water will still be hard

5-Improved pressure

Switch to surface water
 1-Reduced arsenic, iron, manganese and hardness concentrations in water

2-Improved Pressure