Sources of Lead in Well Water

xquercus · 08-31-2012, 06:19 PM

I just had a water analysis done on a house I'm considering purchasing. Among the results is a elevated level of lead at 15.7 ug/l. This house was constructed in 1980 so the plumbing, no doubt, contains lead solder and fittings. However, this was not a first draw test. That is, water was purged from the plumbing for about 15 minutes before taking the sample. It wasn't a test of water which had been sitting around in the plumbing for a long period. This was freshly drawn water which hadn't sat around in the pressure tank or indoor plumbing. I've seen quite a few well water tests and once the indoor plumbing has been purged, they come back either negative for lead or at a very small level. First draw tests might come back this high, but in my experience, not tests which involve purging the plumbing.

Any thoughts as to what this might imply? Could there be enough lead in the fittings in the well to cause this level of contamination? Could the sub pump itself have enough lead to cause this reading? Groundwater contamination? Central Maine isn't an area known for naturally occurring lead in ground water. Anyone have any thoughts or experience about this?

Akpsdvan · 08-31-2012, 08:18 PM

I would be looking at the ph of the water.
Low ph water can leach out lead, copper and other metals out of the plumbing of the house.

xquercus · 09-01-2012, 04:33 PM

The pH is a bit acidic compared to other tests I've seen in this area (Central Maine). Usually I see a straight up 7.0. The well is also unusual compared to others in the area as there is probably about 100 feet of overburden according to the state geological maps. Most of Central Maine is 15 feet to bedrock but this well is in an area of fairly deep glacial sand and numerous small 'kettle ponds'.

I've been doing some reading about well construction and apparently there is likely a lead containing 'packer'. Of course, I don't really know what a packer is but I wonder if it could be contributing to the increased lead level and whether the packer could be replaced -- perhaps the next time the pump needs to be changed out.. On Tuesday I plan to talk with a couple of the local well places and see what their thoughts are.

The bottom line is that the lead will have to be dealt with in order to pass mortgage underwriting. The cheapest solution is probably treatment right at the tap but I'm looking for more information to see if I can actually resolve the underlying cause -- if I purchase the house.

I have some concern regarding the health impact of lead in the water but, frankly, my major concern is future resale. I'd ultimately rather address the source of the contamination than install a filtration system.

Code:

E. coli                        Absent /100mL
Arsenic, Total                 <5.00 ug/L
Chloride, Total                110 mg/L 
** A 1:3 dilution was performed in order to bring the concentration of chloride into the calibration range. The reporting limit has been adjusted accordingly.
Copper Total                   0.059 mg/L
Iron Total                     0.53 mg/L
** The iron level is above the desirable limit of 0.3 mg/L.
Fluoride                       <0.40 mg/L
Hardness by calculation        100 mg/L
Manganese Total                <0.02 mg/L
Sodium Total                   54 mg/L
**Persons afflicted with particular health problems are advised to drink water with a sodium content of less than 20mg/L.
Nitrite-Nitrogen, Total        <0.20 mg/L
Nitrate-Nitrogen, Total        <2.0 mg/L
Lead Total                     15.7 ug/L
** This water is unsatisfactory for drinking due to an elevated lead level above the EPA maximum contaminant level of 15.0 ug/L.
pH Electrometric               6.6
Total Coliform Colilert        Absent /100mL

Akpsdvan · 09-01-2012, 05:33 PM

So the water from the well has no lead?
Or the water from the well that has been setting there for say 12 hours has no lead?

If there is no lead in the straight well water either fresh or setting for 12+ hours then the only other place that the lead is coming from is from in side the house because of the low ph leaching the plumbing.

Correct the ph with either calcite or soda ash injection.