Dangers of Sodium Hypochlorite?

Hey guys,

I read a lot about guys washing vinyl siding on houses and using 12.5% SH and some Simple Cherry (and water of course). That all sounds good- but out here in California, it seems like 95-98% of all newer homes (built within last 10 years) are stucco.

I plan to downstream 10% SH and Simple Cherry for my house wash. Does this seem appropriate? It seems like most of the info I read about is for vinyl. I swear vinyl is so rare out here- i might not even recognize it when i see it. Seriously, you can drive for blocks and blocks and see nothing but stucco. Only on older homes do you see anything other than stucco.

Also, while using the 10% SH, what do I need to worry about on a home? I know that I need to pre-wet the plants, or cover them, but what about the front door thats made of wood and painted, or what if i get some of this mix on a A/C unit? How about the deck that is in the back (what will it do to the deck), maybe the house address is made of painted wood (should I cover it first)? Silly questions maybe, but I still would rather ask someone than find out the hard way.

Basically I’m just trying to figure out what kind of things I can damage with 10% SH. It seems to me that there would many things that 10-12.5% sodium hypochlorite would damage or fade. For concrete and such it seems pretty obvious to just keep it wet and rinse it thoroughly, but spraying on a house- there seems to be many things that are going to get wet that I did not intend to get wet.

While I read a lot of great info from the pros on the forums, I also realize that the pro’s might just assume that one would know not to put this “chemical” on that “surface” etc. I don’t want to be the ass that makes everyone look bad by going out and damaging someone’s house just because i never heard anybody ever mention that you cant just spray and pray with a bunch of chems on a house.

So how about it guys? what CAN i damage on a house with a typical house wash mix?

Your experience and knowledge are invaluable and I appreciate that you guys see fit to spread it around.

Thanks all,


Sodium hypochlorite is sodium hydroxide and chlorine so I would try just a 10-20% bleach wash,then use a 80deg. tip to give you a soft wash then use a HVLP-high volume low pressure tip to rinse down ,make sure to give it a good rinse,if you don’t there is a small chance of leaving yellow spots on the stucco.Dont use any type of high pressure on stucco because there may be small cracks or chips in the stucco and that could cause alot of damage.
Invisaclear Window Cleaning
Toledo OH

Sodium hypochlorite IS NOT sodium hdroxide. They are two completely different chemicals. Don’t get them confused. Sodium hyporchlorite is considered bleach. Sodium hydroxide is a main ingredient in stripping decks and gutter polishing. It can cause potentially more damage and completely different results if you don’t know how to use it.

You’ve probably read the ingredients on the back of store bought bleach. Sodium Hypochlorite is the main ingredient, 2nd to water of course. They do add a slight amount of sodium hydroxide - it’s my understanding that this is added as a stabilizer as sodium hypochlorite has a very short shelf life. The two cleaners are very much different and serve different purposes.

When you’re down streaming, you won’t be applying that 10% sodium hypochlorite at full strength. You only need between 1% and 2% of bleach to effectively kill and clean mold and algae. So for down streaming you would fill you solution bucket with water, add the appropriate amount of sodium hypochlorite, and then a surfactant to help with cling and rinsine. Simple Cherry is a good surfactant, but there are many more available too.

For stucco cleaning, I would strongly recommend “Soft Washing”. You can down stream all your cleaners as low pressure onto the home, allow for proper dwell time, and then rinse everything off at low pressure. You achieve low pressure by increasing the orifice size of the tips. For instance, if you’re running a 4 GPM machine, you can use a 10 GPM tip with a 40 degree fan spray. That’s the exact nozzle shown in my avatar picture. Very soft, but yet effective - and great for cleaning stucco. You can use other nozzles to reach higher distances, such as a 0 degree - 60 GPM tip. That’s the only 0 degree nozzle you should ever use!

When your hitting the house with 1-2% sodium hypochlorite you will want to pre rinse the plants. Keep them rinsed off and do a through rinsing after cleaning the home. You don’t want any cleaner to dry on the plants - but this is pretty simple to prevent. Just rinse plants while you’re allowing your cleaner to dwell on the house. You shouldn’t have any problems with the cleaner on a deck - provided it wasn’t just stained yesterday. You would want to cover the entire deck in cleaner tho, and just rinse it off when you’re done. I usually charge a little extra for “Deck Rinsing” - Deck Rinsing is very different then “deck cleaning” however. Another thing to remember, make sure you rinse the windows really well to prevent streaking.


Hey guys thanks for the info,

So Micah, I should actually spray down their entire deck with the housewash then quickly rinse? Is this so that if I am doing the housewash and I get chems on the deck it will all blend in since I have already “rinsed” the deck with the housewash? Or are you doing that just to be nice to the customer?

Also how do you know- or figure out what ratio your injector is pulling chems? I never quite figured this out.

I will be running a 3gpm (i know-i know, I’ll be getting a 4 or 5.5 as soon as poss) at 3000psi. I will be using the Adams injector and #30 for soap nozzles and #9 for rinse nozzles (per Bob @ Pressurtek). I’m thinking 0 deg for the high stuff and 40deg for up close? How does that sound for 3gpm machine? Or should I go 65deg?

Thanks again for all the info,


I use 4 nozzels. Soap high, rinse high, Soap low, rinse low, (Jrod). Works great.

I thnk what Micah is saying is to do the whole deck so it all blends in stead of the run off cleaning just a small part and it stands out.

Yeah that’s what I figured he meant.

Your setup sounds like what I’m going to do as well. I’m glad you like yours:cool:

I use that system too. It’s fantastic!!!

Micah’s post was right on… I usually clean with 1% or less Sodium Hypochlorite unless there is a tough spot that is harder to clean.

About the sodium hydroxide / hypochlorite deal… sodium hypochlorite is made by difusing chlorine gas through sodium hydroxide. Check out wikipedia, its got more on this if you want.

Has any body powerwashed a vinly house using sodium hydroxide (12.5) and water with simple cherry and caused the siding to turn white. A customer just called me and told me that a large white spot was noticed on his vinly siding

I would not work with chemicals every day. Sometimes we need them but not for homes.

I hear ya. I’m hesitant to just spray chems everywhere but I also realize that sometimes you just have too. That’s why I try my best to find as much info as possible about any chem I use as well as alternitives.

Do you do house washing? If so what chem do you use? If no chems what is your house washing process?


I use sodium hypochlorite all the time in house washing. For house washing you only need 1.5-3% of SH hitting the house. I usually start at about 1.5-2% -That’s not a dangerous solution, it will barely even stain your shirt. Rinse the plants before, during and after and you’ll be fine.

Altering the color of vinyl siding with the correct % of SH isn’t likely. SH in these low concentrations is fine for vinyl siding and it’s the preferred method of cleaning. Perhaps an area is cleaner than the rest? Maybe the stain was there hiding under a thick layer of algae or dust? Take a look at the house and see what it looks like. I

Front Runner must like working too hard. Anything over 100 psi on a homes exterior is not needed and increases chance of damage.

We stay away from chemicals as much as possible.

You don’t have a lot of mold and mildew out in California, either.
You have to kill it before you remove it or you’re just wasting the homeowner’s money and risking damaging their property.

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how are you able to remove mildew and mold using 1-2%? What else do you add to the solution?

you can add a surfactant but all you need is SH aka bleach and water.

Look into down streaming or soft washing.

Super easy

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I’m impressed, a 10 year old thread resurrected.

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Lol, I know. I started seeing some of those old names and I was like, wait a minute…