Chlorine or Bleach for house wash?

As I’m new to the industry I’ve been reading and reading and reading and reading some more, I have only ever been able to find comments leading to bleach in lieu of chlorine. Having said that I was at my local pressure wash store today and was told by someone who has been in the business for going on 30 years (17 of which were spent running a business performing house wash etc…) that I should be using liquid chlorine from the pool store. He said bleach is absolutely fine but chlorine is the way to go. Thoughts are very welcomed, thanks in advance for your thoughts and comments.

Liquid chlorine and bleach are pretty much the same thing: Sodium Hypochlorite. Store bought bleach might contain some additives, but it’s still Sodium Hypochlorite. For our purposes, it’s the same.

You can usually find a stronger concentration of Sodium Hypochlorite at pool stores (10%), than you can in grocery stores (8.25%). Many people buy the Sodium Hypochlorite in bulk from chemical suppliers, which is the strongest you can get it (12.5%).

Im assuming he said what he did, because he knows that 10% bleach will work better than 8.25% bleach… but not sure why he didnt explain the difference, or why he made it seem like they are different chemicals. Of course, he might not understand that bleach and liquid chlorine are the same thing, in which case, i wouldnt take advice from him.

Look at a jug of bleach the next time you are in the store… it will say Sodium Hypochlorite on the side, and will give the strength.

In its elemental state chlorine exists as a gas. Gas is available for swimming pool sanitation. It is very cheap, and is the purest form of chlorine with no binders or carriers. The percentage of available chlorine is 100%. It is also extremely dangerous and restricted in its use. It is rare to find a pool using gas as a sanitizer, and those that do are usually very old, very large public pools that have (we hope) enacted strict safety procedures. Chlorine gas is very acidic, with a pH close to muriatic acid, so these pools using it add a lot of base to counteract this.

Liquid chlorine is another type which is created by bubbling the chlorine gas through a solution of caustic soda. The yellow liquid (stronger, but chemically identical to bleach) has 10 - 15% available chlorine, and has a very high pH, on the other end of the scale at 13. Pools using liquid chlorine for sanitation will add a lot of acid to the pool, to counteract this, and lower the pH down into proper range.

Liquid Chlorine is called Sodium Hypochlorite (NaOCl), and because it is already in solution, ‘sodium-hypo’ produces hypochlorous acid instantly when it contacts water. The liquid can be poured directly into the pool but it is recommended to use a diaphragm pump or a peristaltic pump to inject it into the plumbing. The use of liquid chlorine is more dominant in larger commercial pools which have it delivered by trucked and pumped into 55 gallon vats. For most residential pools, the lower cost may be outweighed by its difficulty in use and the amount of acid required to counteract its pH of 13. Use care when handling as this chemical is corrosive to just about everything.


Great info right there, thank you!

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Could someone please explain to me how using 10% vs 8.5% bleach is stronger? Can’t you just adjust your ratio and have the same end result?

You can. I use 12.5 because it is cheaper than the jug stuff, takes up half the storage space, and no one delivers 6%

As long as you are wanting to achieve a concentration no higher than 8.5%, then yes, they are the same. You can bring an 8.5% jug down to 4% for a roof, just like you can for a 10% jug.

Downstreaming and xjetting adds water, which dilutes the bleach, even if you are pulling it right out of the container. So often guys want a stronger starting concentration, so they can downstream or xjet without it being too diluted for whatever challenge they are facing. Also, sometimes people need straight bleach from a pump up or dedicated pump, to treat a particular surface. The stronger the better, in some cases.

And yeah, like IB said, buying the strong stuff usually works out to a cheaper cost overall, because you can cut it.


Makes sense. I have just been using whatever bleach is cheapest at the store. Seems to be working fine. Cleans those houses right up.

So in florida, most homes are stucco. I need a way stronger mix than down streaming can provide. I’m making a roof setup now so it can be strong enough to handle bad stucco jobs and now roofs (finally). I use 10% so that in a 50/50 mix would be ideal for me. God I wish we had more vinyl.

More vinyl in the hurricane state lol. Don’t think that would go over to well. I breeze right through those stucco houses. Xjet one side at a time then rinse. The soffit is worse than the stucco in my experiences.