Lead in Domestic Hot Water -- Hot Water Heater?

Jamie Hall

doesn't mean that someone didn't use lead solder. Unlikely to be the W-M equipment.

Ron S_2

Lead in Domestic Hot Water -- Hot Water Heater?

568ppb lead levels in my DHW! My water supply company called me Friday night to inform me of these high levels after I had the water tested because I was getting what I thought were lime-like buildups on my shower floor and pinhole leaks.

According to Suffolk County Water, their cold water input tested fine, but both the scrapings from the shower floor and water taken off the hot water supply showed very high lead.

Their conclusion was that it was likely to be the Indirect Water Heater -- a Weil McLain Gold Plus 60 installed in '04 attached to a GV Gold gas boiler. Buildups became evident on the shower floor in '06. We have a recirculating DHW system and radiant heat throughout. Most of the plumbing is new as it's mostly new construction. The indirect WH has never been flushed.

Very concerned about these lead levels! Any thoughts?

Thanks as always,
Ron

PJO_5

How old is the feed...

to the house?

If it's from the late 30's to mid 40's it could be lead. How do I know? I had a duplex in NE Philly that was built around that time...had the water and sewer lines replaced and when they pulled out the old water feed - whoa! It was pure lead...

Take Care, PJO

Maine/Baltimore Doug_6

In Baltimore

I was talking to a guy in Public Works about the relining project going on where I live. I asked about lead pipes and he confirmed that in some parts of the city lead pipes are still in use. Since I only drink wine and single malt and beer I guess I must be lead free 87 octane and contain 10% ethanol.

Doug_7

High Lead Levels in DHW

568ppb lead levels in DHW is very very high. Safe level in drinking water in Canada is 0.01ppb.

I would not jump to the conclusion that the source is the Weil McLain Gold Plus 60 - it is a stainless steel tank.

A more likely source is the DHW recirculation system. DHW recirculation systems with over 2 or 3 feet per second water velocity are subject to velocity assisted corrosion that causes wall thinning of copper pipe and pinhole leaks. I have see complete perforation of the copper pipe inside soldered fittings that exposes the solder to velocity assisted corrosion. This is a theory that needs to be checked out.

The article below covers some lead levels in drinking water that are of concern because that are 2, 5 or 25 times the safe level. You are 50,000 times the safe level.

http://www.cbc.ca/consumers/market/files/health/leadwater/tests.html

They distinguish between "first drawn" and "flushed" levels. Firsh drawn samples contain lead contamination from the stagnant brass fixture. Flushed samples are more representative of the water supply.

Questions:

- Is there any connection between your hydronic heating system and your DHW system ?

- Is this all copper pipe with 50% lead solder ?

- Does DHW recirculation coincide with the start of the problem ?

I would immediately flush your DHW system - at least three complete drain-downs and refills. Flush all fixtures and lines with each flush.

I would leave your DHW recirculation system shutdown until you rule that out as the source of lead.

Then test for lead again - using flushed samples.

All schools in Ontario are required to flush all drinking water headers and water fountains for 5 minutes each morning before the students arrive to remove lead from stagnant drinking water left in brass fixtures.

Keep us posted on progress.

Don't drink water from the hot water tap.

Think PEX if you decide to replace the piping.

Doug

Doug_7

Ron - Source of water sample ?

Ron - can you comment on where and how the high lead content water sample was taken ?

If it was the first discharge from a tap, it can be greatly influenced by the metallurgy of the tap and how long it was stagnant.

If it is the first discharge of a virtually unused tap like the DHW tank drain, the lead content may be very high because it was stagnant inside the fixture for a very long time.

When testing water samples in the 0.01ppb range, a great deal of care must be taken in choosing the sample point and in deciding whether it is to be flushed or not before the sample is taken. If you flush for 3 minutes you are checking the water. If you do not flush you are checking the fixture.

If it was taken from a well flushed source - you have a lot of lead leaching from somewhere.

So where and how was the sample taken ?

I would take another sample from a well flushed source.

Doug

Charlie from wmass

Brass fittings and faucets that are stagnent leach out lead. often with the indirect heater style you have brass couplings are used to connect to the heater to reduce leaks at the tank. 50/50 lead solder and lead supplies from the main all contribute. The water department should be able to confirm what the supply is between the main and you meter.

Ron S_2

Lead in Domestic Hot Water -- Response to Responses

PJO & Main/Baltimore Doug: the feed is probably early 1950's. Quite sure it's copper. Domestic cold water showed no lead.

Jamie: regarding the solder, the vast majority of the plumbing is new (2004), installed by a "reputable" plumber. The water authority considered this a possible source but decided lead solder probably wasn't the issue because they saw trace amounts of tin and antimony in the water.

Doug: I actually posted regarding the pinhole leaks a couple of months ago, and the velocity could be a real issue. I have since throttled down the ball value between the Taco recirculator and the HWH. Don't know if these problems are related. The water authority doesn't think so.

I don't recall when the water authority field technician tested if he flushed or not. Perhaps I should have the water tested again with an independent tester or someone who can give me some impartial advice? (Who?)

Regarding whether the domestic hot water coincides with the hydronic system, I doubt it. The hydronic is taken off the primary loop that goes from the boiler and feeds the supply and return of the HWH.

The recirculation system was installed along with the entire boiler/HWH in 2004, along with the vast majority of the plumbing in the house.

Regarding the source of the tests, I remember that one test was taken just off a tap just before the recirculator and return to the HWH. I suspect that this was not flushed. However, another test was taken in the bathroom which is showing the lime-like (but comprised largely of lead) buildup on the floor. That water was probably run for 30 seconds minimum to bring it up to temperature before testing. Cold water was taken from several faucets in the house.

BTW -- the water authority person suggested that the "sacrificial anode" of the HWH be checked but didn't know if flushing the system at this point would be a good idea after several years. He also indicated the chlorine and lime are added to the water, the latter causing the coating I'm seeing on the inside of the copper pipes.

Thanks so much --

Ron

Charlie from wmass

sacrificial anode rods are not used in stainless steel heaters to my knowledge. 1950's 50/50 solder was solder of choice.

Doug_7

Correction

Correction - the safe level in drinking water in Canada is 10ppb - the media got it wrong.

Makes you 50 times too high - which could be accounted for by a "first drawn" sample or contaminated sample - a tiny piece of scale off the tap fell into the sample.

Recheck a well flushed sample taken carefully to avoid stagnant water or contamination from the tap. Wipe the tap water outlet thoroughly with a rag before flushing.

Test only well flushed samples (3 minutes) - not stagnant ones - and never touch the tap when taking the sample.

You don't have a water softener do you ? They can make the water more corrosive.

Normal water is slightly alkaline and the water pipe is normally coated on the inside with calcium based scale which retards corrosion and metal pickup. A water softener can change all that.

I will bet your water authority knows little about velocity assisted corrosion in DHW recirculation piping - but I am sure they know how to test for lead. Discuss and agree on the sampling method.

Doug