The bottled water our company uses has the number 8 on the bottom of the bottle. It’s a stand alone 8 without the recycling symbol. I know the numerical range is 1 to 7 for plastics.
If anyone has information about the numbers outside the normal range please share.
Also the number is 8 on all bottles. Not deformed 6. Thanks
Could you take a picture of the bottles in question an post to an image sharing site?
Also, welcome to the SDMB. 
If it’s not inside the “chasing arrows” recycling symbol, it may not have anything to do with the composition of the bottle. Maybe it’s the volume of the container (8 gallons?).
–Mark
Asked in 2011, with no answer: Plastic #8 - Factual Questions - Straight Dope Message Board
8 gallons would be almost twice the standard size (5 gallons), and pretty freakin’ heavy.
Maybe it’s upside down?
Oh, wait…
Maybe it’s sideways and it’s actually infinity gallons.
–Mark
Go around your house and take a sampling of plastic containers. In addition to the recycling code, many of them have another number on them. I just looked at about half a dozen, and found them to vary from 2 to 39, and a couple of them have a prefix like “SP”. I’m guessing they’re just manufacturer’s codes which won’t make a lot of sense to us. Perhaps the manufacturer makes bottles of a particular style in # 1,2,3, … etc.
Actually, I’ll amend that a bit. I just looked at 4 plastic tubs for the same brand of sliced pastrami, which I save because they make convenient storage containers - they are identical except for the number - there are 4 different numbers: 37, 24, 13 and 67. More likely a lot or manufacturing facility number of some sort.
Mold number.
That makes sense. Good.
I worked as a supervisor at a small plastics blow molding company a long time ago. We were all about the high margin custom limited runs and maxed our at 2-3 hed machines that made 2-3 parts per cycle. The major companies in the market tended to run 16+ head machines for smaller size parts. Even with our small capacity some of our molds for the multihead machines were marked. It made diagnosing and fixing quality issues easier. In the period where I still automatically paid too much attention to bottle quality, I saw a lot of markings that seemed to be nothing but internal use.
Are there ever numbers different than 8?
Thanks for the replies. I opened other cases and found bottles with different numbers on them, 11, 29 etc. Must be a manufacturer code. The paper label of the water company has a recycling symbol on it but no number.
Well…Just called the water company and they didn’t have a clue what type of plastic is used to put their water in. They said they will check and get back with me.
I will post my findings.
Lucky hydrating.
I’m gonna tender a guess of polyethylene terephthalate (PET or PETE). Primary plastic used for water bottles and carbonated soft drink bottles.
From the rather famous Klein Manufacturing?