It seems that nouns that follow "sans" don't necessarily need determiners. This is especially true for uncountable things, e.g. water (a mass noun) or fear (an intangible). Note that a determiner can be placed after "sans". If you want to say "without a dog", you would have to write "sans un chien".
My French friends told me that this is just a weird quirk that you have to learn.
I refute this. The statement "with a preposition, a noun does not need an article" is false.
French prepositions generally fall into two categories:
require the use of the article before their object
sometimes require and sometimes do not require the use of the article before their object
So, some prepositions will need an article. "Avec" and "sans" are prepositions that do not necessarily need articles.
What DXLi said should be correct. Which prepositions require articles and which don't is a quirk you'll need to memorize.
I am not a native French speaker, but this grammar rule is laid out clearly in English on pages 441-442 of this French grammar book: https://play.google.com/store/books/details?id=DBYBAAAAYAAJ
I would say you cannot. Be careful there, avec and sans do not behave the same:
- Without an article, you can say sans eau (which is the most usual way to say that), and you maaaay hear avec eau (but this is very uncommon).
- With le, sans l'eau means without the (this very) water, and avec l'eau BOTH MEANS with the (this very) water and with water (in general). On s'hydrate avec l'eau, on se déshydrate sans eau, we stay hydrated with water, and we get dehydrated without water. Arguably, avec de l'eau sounds better, see following case.
- With de l', sans de l'eau sounds very weird, and you probably don't want to use that. Avec de l'eau, on the other hand, means with some water and is completely fine.
I hope this clarifies a little bit your problem.
eau, eaux (waters), au, aux, oh, haut, aulx (plural of "ail" (garlic), never used but it exists) are all pronounced the same.
There's also the plural of "os" (bone). This one is weird because it's written the same in the singular and in the plural, but pronounced differently. "un os" is pronounced /os/ whereas "des os" is pronounced /o/ . Though a lot of French people don't know this rule and pronounce both forms /os/ .
That's French for you! ^^
The partititive article is omitted after certain prepositions such as "sans", "en" and "par".
It is also omitted after the preposition "avec" when an abstract noun follows and when "avec" has the meaning of "qui a"/"who has".
- A Complete French Grammar for Reference and Practice, page 230, Trudie Maria Booth