|
|
Disinfected
(with chlorine)
|
Treated at Richard A.
Reynolds Demineralization Plant
|
Treated at Robert A.
Perdue Water Treatment Plant
|
|
|
Inorganic Contaminants
|
MCL
|
PHG (MCLG)
|
Range and Average
|
National City Well #2 (before treatment)
|
National City Well #3 (before treatment)
|
San Diego Formation Wells 1 thru 5 (before
treatment)
|
Lake Skinner Outlet (Aqueduct,
before treatment)
|
Sweetwater Reservoir (before treatment)
|
Sweetwater Authority Drinking Water (after
treatment)
|
Typical Source of Contaminant
|
|
Fluoride (ppm)
|
2
|
1
|
Range
|
0.33
|
0.40
|
0.15 - 0.321
|
0.20 - 0.24
|
0.28 - 0.30
|
0.26 - 0.30
|
Erosion of natural deposits; discharge from
fertilizer and aluminum factories
|
|
Average
|
0.33
|
0.40
|
0.2
|
0.23
|
0.29
|
0.28
|
|
Nitrate-N (ppm)
|
10
|
10
|
Range
|
0.49
|
|
ND - 0.661
|
|
|
ND - 0.49
|
Runoff and leaching from fertilizer use; leaching
from septic tanks and sewage; erosion of natural deposits
|
|
Average
|
0.49
|
|
0.13
|
|
|
0.16
|
|
Alluminum (ppm)
|
1
|
0.6
|
Range
|
|
|
|
ND - 0.053
|
0.12
|
|
Erosion of natural deposits; residue from some
surface water treatment processes
|
|
Average
|
|
|
|
ND
|
0.12
|
|
|
Arsenic (ppb)
|
50
|
NA
|
Range
|
|
|
|
ND - 2.7
|
2.3
|
|
Erosion of natural deposits; runoff from orchards,
glass and emectronics production wastes
|
|
Average
|
|
|
|
2.1
|
2.3
|
|
|
Barium (ppm)
|
1
|
(2)
|
Range
|
|
|
0.055 - 0.1001
|
|
|
|
Erosion of natural deposits; discharges of oil
drilling wastes and from metal refineries
|
|
Average
|
|
|
0.081
|
|
|
|
|
Lead (ppb)
|
AL=15
|
2
|
Range
|
|
|
0.7 - 7.21
|
|
|
|
Discharges from industrial manufacturers, erosion
of natural deposits
|
|
Average
|
|
|
2.3
|
|
|
|
|
Organic Contaminants
|
|
Toluene (ppb)
|
150
|
150
|
Range
|
|
|
|
ND - 0.7
|
|
|
Discharges from petroleum and chemical factories;
underground tank leaks
|
|
Average
|
|
|
|
ND
|
|
|
|
Radionuclides (a)
|
|
Gross Alpha (pCi/L)
|
15
|
(none)
|
Range
|
ND - 2.1
|
ND
|
ND - 12.11
|
ND - 6.221
|
ND - 1.71
|
|
Decay of natural and manmade deposits
|
|
Average
|
0.7
|
ND
|
5.6
|
4.05
|
0.6
|
|
|
Gross Beta (pCi/L)
|
50
|
(none)
|
Range
|
|
|
|
4.18 - 7.421
|
|
|
Decay of natural and manmade deposits
|
|
Average
|
|
|
|
5.52
|
|
|
|
Uranium (pCi/L)
|
20
|
0.5
|
Range
|
2.08 - 3.19
|
1.46 - 3.99
|
ND - 6.461,
2
|
ND - 3.671
|
3.83 - 4.07
|
|
Erosion of natural deposits
|
|
Average
|
2.64
|
2.73
|
3.0
|
2.55
|
3.95
|
|
|
Turbidity (b)
|
|
Combined Filter Effluent Turbidity (NTU)
|
TT
|
no standard
|
Highest single measurement
|
0.38
|
Soil runoff
|
|
Lowest monthly percent of samples meeting MCL
|
100%
|
|
Unregulated Contaminants
|
|
Perchlorate (ppb)
|
NA
|
AL=18
|
Range
|
|
|
|
ND - 6
|
|
|
EPA regulations require us to monitor this
contaminant while EPA considers setting a limit on it.
|
|
Average |
|
|
|
4 |
|
|
|
Vanadium (ppb)
|
NA
|
AL=50
|
Range
|
|
|
|
4 |
|
|
EPA regulations require us to monitor this
contaminant while EPA considers setting a limit on it.
|
|
Average |
|
|
|
4 |
|
|
|
Boron (ppb)
|
|
|
Range
|
|
|
|
120 - 130 |
|
|
EPA regulations require us to monitor this
contaminant while EPA considers setting a limit on it.
|
|
Average |
|
|
|
130 |
|
|
|
Unregulated Radiological
|
|
Radon (pCi/L)
|
No standard
|
Range
|
270
|
270
|
|
|
|
|
Decay of natural deposits
|
|
Average
|
270
|
270
|
|
|
|
|
| |
|
Water Distribution Regulatory Compliance
|
|
Organic Chemical Contaminants
|
|
Total Trihalomethanes (TTHMs) (ppb)
|
100
|
Not applicable (c)
|
Highest running annual average
|
|
|
|
|
|
274
|
By-product of drinking water chlorination
|
|
Range of all distribution sample points
|
|
|
|
|
|
2.7-82.9
|
|
Lead and Copper Rule |
# of sites found above AL
|
90 percent of samples below
|
|
|
Lead (ppb)
|
AL=15
|
2
|
5 sites above AL out of 50 sites sampled
2
|
|
|
|
|
|
13.52
|
Corrosion of household plumbing systems
|
|
Copper (ppb)
|
AL=1300
|
170
|
1 site above ALout
of 50 sites sampled 2
|
|
|
|
|
|
5502
|
Corrosion of household plumbing systems
|
|
Microbiological
(c)
|
Highest monthly percentage
|
|
|
Total Coliform Bacteria
|
5.0%
|
(0)
|
# of positive samples taken this year = 0
|
|
|
|
|
|
0
|
Naturally present in the environment
|
|
Fecal Coliform Bacteria
|
(c)
|
(0)
|
# of positive samples taken this year = 0
|
|
|
|
|
|
0
|
Human and animal fecal waste
|
| |
Disinfected
(with chlorine)
|
Treated at Richard A.
Reynolds Demineralization Plant
|
Treated at Robert A.
Perdue Water Treatment Plant
|
|
|
Inorganic
Contaminants
|
Secondary MCL
|
Range and Average
|
National City Well #2 (before treatment)
|
National City Well #3 (before treatment)
|
San Diego Formation Wells 1 thru 5 (before
treatment)
|
Lake Skinner Outlet (Aqueduct,
before treatment)
|
Sweetwater Reservoir (before treatment)
|
Sweetwater Authority Drinking Water
(after treatment)
|
Typical Source of Contaminant
|
|
Iron (ppb)
|
300
|
Range
|
|
110
|
50-4201
|
|
230-440
|
|
Leaching from natural deposits; Industrial wastes
|
|
Average
|
|
110
|
155
|
|
335
|
|
|
Manganese (ppb)
|
50
|
Range
|
|
|
77-19001
|
|
19-490
|
ND-105
|
Leaching from natural deposits
|
|
Average
|
|
|
638
|
|
255
|
45
|
|
|
Specific Conductance (microseimens/ centimeter)
|
1600
|
Range
|
1006 - 1255
|
1115 - 1262
|
1750- 42581
|
802-856
|
821-1093
|
727-1157
|
Substances that form ions when in water; Seawater
influence
|
|
Average
|
1113
|
1202
|
2602
|
823
|
982
|
953
|
|
Total Dissolved Solids (ppm)
|
1000
|
Range
|
569
|
635
|
970-20251
|
486-516
|
301
|
136-592
|
Runoff/leaching from natural deposits; Seawater
influence
|
|
Average
|
569
|
635
|
1482
|
497
|
301
|
303
|
|
Chloride (ppm)
|
500
|
Range
|
181-215
|
186 - 217
|
410-7071
|
70-79
|
112-151
|
79-217
|
Runoff/leaching from natural deposits; Seawater
influence
|
|
Average
|
207
|
207
|
592
|
73
|
133
|
161
|
|
Sulfate (ppm)
|
500
|
Range
|
46
|
63
|
103-2381
|
168-184
|
164
|
11-166
|
Runoff/leaching from natural deposits; Industrial
wastes
|
|
Average
|
46
|
63
|
180
|
178
|
164
|
32.4
|
|
Sodium (ppm)
|
NS
|
Range
|
150
|
170
|
290-7401
|
77-88
|
100
|
90-110
|
Runoff/leaching from natural deposits; Seawater
influence
|
|
Average
|
150
|
170
|
414
|
82
|
100
|
100
|
|
Hardness (Total Hardness) (ppm)
|
NS
|
Range
|
182 -211
|
290 - 211
|
247-6761
|
278-291
|
256-307
|
33-320
|
Leaching from natural deposits
|
|
Average
|
189
|
201
|
434
|
283
|
380
|
175
|
