In a libertarian place everyone would have access to water (for example) through the market.

This looks ideal, only if there is fair competition. How there can be a fair competition if there is no regulations to avoid things like monopoly, price dumping, cartel, and all other practices that hurt a fair market?

That is one thing that libertarians still didnt gave me a acceptable answer.

Saying that the market regulates itself is to ignore all the monopolies, dumping, and cartel created on the past that were held by market regulation laws.

Like in this case of water, someone monopolize the water supply of a big enough region he puts very high price that only very rich people can pay it. No one else can enter the competition to bring prices down because de monopoly already owns all water sources on a big area.

All he have to do is have a price low enough that it makes not profitable to anyone to bring water from places outside the region.

To ilustrate:
The fair price (costs+acceptable profit) of extracting water on a big region would be $10,00 per gallon.
The price to bring water from outside this region (extraction+transport costs+profit) would be $200,00
The owner of the water monopoly only need to set the price to $199,00 so that no one outside the area would have interest in selling there.

Is if a fair market? Meanwhile, people start doing horrible things and breaking the no damage rule only to survive.

BTW, is the No damage rule applied if the damage was done in name of basic survival, like having water to drink?