BLUE GREEN STAINING FROM LOW pH WATER

BLUE/GREEN STAINING & CORROSION CAUSED BY LOW pH 

Water pH lev­el reflects how acidic or alka­line it is. pH stands for “poten­tial of hydro­gen,” refer­ring to the amount of hydro­gen found in a sub­stance (in this case, water). pH is mea­sured on a scale that runs from 0 to 14. Sev­en is con­sid­ered neu­tral, mean­ing there is a bal­ance between acid and alka­lin­i­ty. A mea­sure­ment below 7 means acid is present and a mea­sure­ment above 7 is basic (or alka­line).  Low pH is a com­mon phe­nom­e­non in New England’s water sup­ply.

Acidic water can leach met­als from pipes and fix­tures, such as cop­per, lead and zinc. It can also dam­age met­al pipes and cause aes­thet­ic prob­lems, such as a metal­lic or sour taste, laun­dry stain­ing or blue green stain­ing (from dis­solved cop­per) in sinks and drains . You may even expe­ri­ence “pin-hole” leaks in your pip­ing sys­tem which will lead to the poten­tial need for cost­ly replace­ment.  Water with a low pH may con­tain oth­er met­als in addi­tion to the before-men­tioned cop­per, lead and zinc.

The U.S. Envi­ron­men­tal Pro­tec­tion Agency (EPA) does not reg­u­late the pH lev­el in drink­ing water. It is clas­si­fied as a sec­ondary drink­ing water con­t­a­m­i­nant whose impact is con­sid­ered aes­thet­ic, even though the results of water with a low pH can be dev­as­tat­ing to the water qual­i­ty once it reach­es a home or oth­er end user point. How­ev­er, the EPA rec­om­mends that pub­lic water sys­tems main­tain pH lev­els of between 6.5 and 8.5, which is a good guide for indi­vid­ual well own­ers, how­ev­er, symp­toms as pre­vi­ous­ly described are an indi­ca­tor that cor­rec­tive action may be nec­es­sary.  You may very well see stain­ing and oth­er issues with water toward the low­er or high­er end of this range.

HIGH pH or ALKALINE WATER

Drink­ing water with a pH lev­el above 8.5 indi­cates the pres­ence of a high lev­el of alka­lin­i­ty. High alka­lin­i­ty does not pose a health risk, but can cause aes­thet­ic prob­lems such as an alka­li taste to the water that makes cof­fee taste bit­ter, scale build-up in plumb­ing, and low­ered effi­cien­cy of elec­tric water heaters. High­ly min­er­al­ized alka­line waters also cause exces­sive dry­ing of the skin as they tend to remove nor­mal skin oils.

Low pH dissolving copper from pipes

WATER TREATMENT FOR LOW pH

Two home treat­ment meth­ods to adjust pH are acid neu­tral­iz­ing, point of entry fil­ters and chem­i­cal feed pump sys­tems inject­ing a neu­tral­iz­ing solu­tion.

An acid neu­tral­iz­ing fil­ter uses cal­cite or ground lime­stone (cal­ci­um car­bon­ate) for pH cor­rec­tion, but could also include a blend of mag­ne­sium oxide and cal­cite if the pH is very low. (The affect is kind of like a giant food-grade “Tums” slow­ly releas­ing into the water to neu­tral­ize the acid).  Since the water absorbs these min­er­als when it pass­es through the fil­ter, the alka­lin­i­ty and hard­ness will increase.  Hard­ness is eas­i­ly treat­ed with a water soft­en­er that uses an ion exchange process to remove the hard­ness min­er­als. The result of this two-step process is neu­tral pH with soft­ened water.

A chem­i­cal feed pump solu­tion is made with well water and soda ash (sim­i­lar to bak­ing soda) and mixed in a solu­tion tank. The chem­i­cal feed pump injects this high pH solu­tion into the house­hold pip­ing sys­tem where it reacts with the low pH water in a reten­tion tank (typ­i­cal­ly 40 gal­lons) and neu­tral­izes the pH.  Neu­tral­iz­ing with soda ash slight­ly increas­es the sodi­um con­tent of the water which may pose addi­tion­al health con­cerns if some­one in your house­hold is on a reduced sodi­um diet.  This can be addressed with a reverse osmo­sis drink­ing water sys­tem which desali­nates and puri­fies water to a very high degree.

Your water treat­ment pro­fes­sion­al, after ana­lyz­ing your ini­tial water test results, will be able to make a deter­mi­na­tion as to the best approach for you.

For more on water pH, see the link at Low pH link.