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Participant

Join Date: Sep 2010
Location: Maryland
Posts: 3

How to Flush Iron Residue from PVC Household Pipes?

09/06/2010 8:41 AM

Is there any chemical flush that could be used to safely and easily remove the rusty colored iron coating from the inside of PVC fresh water pipes in a house? The system is on well water and there is a neutralizer and softener at the entry point. I am trying to find a way to clean the distribution lines after those.

Thanks!

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Guru
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#1

Re: How to flush iron residue from PVC household pipes

09/06/2010 8:56 AM

Maybe citric acid, though if there is Fe precipitation downstream of the softener then the resin in the softener will have been rendered inoperable by the coating. Solution:

  1. Fit a whole-house filter upstream of the other equipment with a nominal 5μm rating or smaller. Put changing the filter cartridge on a planned preventative maintenance schedule.
  2. Change the softener resin for new. Beware of spillage: the resin beads work like tiny marbles when spilled on a hard floor and the risk of trips and falls will increase unless swept up immediately. Do not consume softened water, as the body needs a low sodium and a minimum calcium level to maintain health - the opposite of what comes out of a softener.

50ppm of Fe is not dangerous, though it won't get fresh washing truly white.

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#2

Re: How to flush iron residue from PVC household pipes

09/06/2010 9:37 AM

There are two chemicals (acids) that could work that are readily available: acetic acid which is found in white vinegar, and hydrochloric acid which is also known as muriatic acid.

White vinegar is much safer to use, of course. All vinegars contain acetic acid, so the vinegar used in foods contains acetic acid which is edible / potable. You might want to test a section first, to see how effective the vinegar is.

If the white vinegar is not strong enough, you could try muriatic acid. Again, test a section first.

In either case, make sure that the acids don't get into your water filtration systems, and make absolutely sure that the acid is flushed from the system before using the water to bathe or drink. Both acids will affect (etch) metal surfaces, so be careful of that, too.

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#3

Re: How to Flush Iron Residue from PVC Household Pipes?

09/06/2010 11:38 AM

I mentioned this trick that works rather well for cleaning out the pipes in another thread but I think its worth repeating (copy and paste with cleanup for what spell check didnt catch, again) here.

As far as cleaning your existing pipes out thats an easy one. Install a valve at the point where the line coming from the well connects to everything else and then hook up an air compressor to it that can pump around 10 CFM or better at close to what your normal water pressure is. Use a pressure regulator of course in order to keep from over pressurizing your water system.

Then go around to each faucet and hydrant you have and open them to full flow while the air compressor is pumping air into the feed line along with the supply water comming from the well. Start with the points closest to the air source and work your way out. The high volume of pressurized air bubbles will pound and shake the sediments and rust deposits out of your lines without problems. Just don't be surprised when the nasty muddy syrup starts to come out at first though.

My brothers place also has a well with a high iron and sediment content so I have to do the air injection cleaning to his place about once every two or three years otherwise the pipes silt in so bad that he looses all of his flow capacity and pressure. It works very well but always makes for a few minutes of very nasty looking sludge being pumped out of everything!

I also did this to my dads place last summer when I changed his old 1940's pump jack system over to a submersible system. For about 20 minutes all we got was nasty orange and brown goo from every hydrant on the farm! But now he has good water flow and pressure everywhere again!

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#7
In reply to #3

Re: How to Flush Iron Residue from PVC Household Pipes?

09/07/2010 12:29 PM

tcmtech we've always been told not to use compressed air in PVC piping systems due to the chance of the pipe and fittings shattering and harming people in the area. I wonder if the water in the system tempers the compressed air ?

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#8
In reply to #7

Re: How to Flush Iron Residue from PVC Household Pipes?

09/07/2010 1:10 PM

I believe tcmtech is talking of having the system open when injecting air!

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Guru

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#11
In reply to #8

Re: How to Flush Iron Residue from PVC Household Pipes?

09/07/2010 2:12 PM

Compressed air doesn't have the carrying capacity for removing solid particle that water would. You would need a much higher flow velocity to remove rust deposits, especially if they are weakly bonded, as rust tends to do. Way eaiser to do the same thing municipalities do and open or remove a valve at a lower end of the system then let the water run at full. go around the house at lower taps and open them individually or in pairs, whatever keeps the flow velocity in the pipes maximized, to flush the dead spaces.

Air lifting the well is a good way to clear the sediments in the bottom, it could take a couple of days if there is a lot of sediment, especially dense particles like iron.

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Participant

Join Date: May 2014
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#13
In reply to #3

Re: How to Flush Iron Residue from PVC Household Pipes?

05/19/2014 10:48 AM

Great Tip tcmtech!!! I replaced all the shut off valves (which were caked with iron to the point you could not see through them) but still had very little water pressure. I tried your trick by hose clamping my air blow chuck to a water hose on a faucet right at the well. I went to the faucet at the house and open the line full blast and then went back to the well and turned on the air at 65 psi (the same setting as the well) and opened the faucet valve. I ran back to the faucet at the house and there was thick red mud coming out in spurts for a good 5 minutes and then slowing clearing in about 10 minutes overall. After I disconnected everything and tried the water at the house I had great pressure again. THANKS for sharing!! I was just about to replace all my lines!

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#4

Re: How to Flush Iron Residue from PVC Household Pipes?

09/06/2010 10:56 PM

You may want to look into a product called RustAid. It works miracles with rust buildup. I have absolutely no idea of the health effects of this product and you should carefully research that before deciding if it is apropriate.

On the other hand the air idea sounds interesting to try. Perhaps a combination of the air idea and a follow on with the Acetic Acid.

Good luck with your pipes.

-Doug

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#5

Re: How to Flush Iron Residue from PVC Household Pipes?

09/07/2010 10:46 AM

I do like TCMTECH's good answer and several other that recommended a mild acid treatment. The problem with acid is the danger of etching faucets, sinks, and fittings. I suspect your plumbing has some of these types.

In addition it is also important to control the iron coming from the well. You may want to consider a well flushing. This can be done mechanically or chemically or both. A mechanical cleanout may require a well driller. However some cleaning can be done by using acid inside the well to breakdown the iron and put in solution so it can be pumped off. The pump should be dedicated to this job. If you use your own pump, it may jamb with the sludge from the well. If you have access to someone who is licensed to clean wells, I would opt in that direction of letting a pro do it for you.

It is my opinion that whenever there is a heavy iron problem from groundwater sources, iron bacteria are present. These are bacteria that are harmless but use iron as an electron sink. The result is to put higher and higher amounts of iron in solution in well water. In addition to these iron reducing bacteria, there will exist iron oxidizing bacteria that will try to take the iron out of solution. This oxidation is aided by the pumping levels within the well.

The solution to control iron buildup is to add a line to the well and use a small solution of peroxide that can be pumped into the Bottom of the well at each pumping cycle, or optionally, pumping a higher level into the well a couple of times a day. Peroxide will minimize the effect of iron reducing bacteria and prevent the attachment to the plumbing and bore hole. You should also use a coarse filter like greensand before the water meets your softener.

Sampling your raw well water for iron, manganese (do both soluble and total Fe and Mn), pH, Total P, TOC, NH3, NO2, NO3, TKN (to get organic nitrogen content TKN-NH3 = organic iron), H2S, and Conductivity is important in evaluating the condition of the well. It is likely an accredited lab specializing in ground water will have good packages for other metals and parameters. Individual parameters testing can be expensive. The objective is to minimize iron within the well and thus within the plumbing.

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#6

Re: How to Flush Iron Residue from PVC Household Pipes?

09/07/2010 12:11 PM

Strong acids are not a good solution for iron removal. Citric acid might be effective since it is a weak chelating agent. the safest and simplest solution is EDTA, which is now commonly available in any rust stain removers you can buy for household use. EDTA doesn't normally effect deionizer resins, though it can strip the ions fromt he surface requiring recharging of the resins. EDTA is a extremely effective chelating agent, which will make the irons deposits soluble. Following treatment and allowed reaction time, then you would need to flush the entire system for a while. EDTA is not particularly toxic, though if consumed in quantity it can extract some calcium from your bones (along with a variety of bioaccumulated heavy metals and radionuclides). Best to flush the lines before re-use.

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Guru
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#9

Re: How to Flush Iron Residue from PVC Household Pipes?

09/07/2010 1:37 PM

There is a commercial product out by the name of C-L-R (name derived from Calcium Lime Rust) which is rather safe to use. It is generally used by soaking or immersing the offending part in it. It can also be used by flushing it through or circulating it through the system. It is available at the big box stores. I would investigate it before using any of the chemicals listed previously in this thread. Yes some of them may work great but all seem to be either very slow in reacting, very fast in reacting or have unwanted side reactions or effects.

If you use the compressed air/water injection method, make sure you have check valves on both the water supply and the air supply. An imbalance of pressure could put water in your air compressor or air into the well or pump, situations which could make this project very expensive and frustrating.

What ever you decide on, put a 5 micron filter in the system after the pump and the tank. This will reduce the amount of rust induced into the system. Remember to replace the filter frequently.

Good Luck, Old Salt

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#10
In reply to #9

Re: How to Flush Iron Residue from PVC Household Pipes?

09/07/2010 2:06 PM

CLR is a Proprietary organic acid solution of gluconic and lactic acid. Since they can inject EDTA directly into the blood stream (you definitely would not want to do that with lactic or gluconic acids), I suspect CLR is more toxic. Plus it can cause digestive distress if ingested, and irritate exposed skin in contact. Plus CLR is a buffered acid based reaction which would depend highly on concentration at point of contact, standing water in pipes would dilute the reaction. EDTA is a chelating reaction that makes the iron soluble, so water slows the reaction due to dilution, but doesn't stop the reaction due to increased pH. Iron is soluble in very low pH (high acidity) or through chelation. Other common household rust and calcium removers utilize chelation from EDTA and a few other compounds, it works well in toilet bowels where there is long reaction time so dilution effect of large volumes of water on reaction kinetics doesn't become an issue.

Honestly, however, I would not worry about removing rust in the pipes as any method will also remove the protective calcium carbonate layer. Rust sediments in the pipes should just be flushed out of the piping systemby opening the lowest valve points and letting the water run full (or maybe removing a lower tap and turning the water main on). Rust in the pump piping is a different situation the pump should be operated at full for some period of time to flush the piping, discharging to the ground somewhere. Rust in the sediments in the bottom of the casing require the well be re-developed. Iron reducing bacteria, which make iron in the aquifer soluble as Ferrous iron that then precipitates as Ferric iron (rust) when exposed to air is a ongoing battle, as the iron reducing bacteria will continuously recolonize the aquifer around the well and must be disinfected recurrently. Activity in the well may have dislodged rust from the side of the casing, the casing should probably be video inspected for condition, as any future activities could cause a collapse or just comntinue to dislodge rust.

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#12
In reply to #10

Re: How to Flush Iron Residue from PVC Household Pipes?

09/07/2010 2:21 PM

RCE-

Thanks for the information. Although I didn't mention it, any use of any chemical in the drinking water system should be followed with large quantities of water to remove any traces of the treatment chemical.

In industry, if the water was for product we only used lab approved water with minimum amounts of iron. For cooling use we would use rusty water if necessary after filtering it and periodically acid treat the piping.

Never had rusty home water because I have always had city water. Have maintained an in-laws summer bungalow with rusty piping and did a very extensive replacement of piping, water heater and installation of filters to get rid of the rust from the well and surrounding water. 3 years later they put in city water because of polluted wells in the area!

Old Salt

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