Кислотность воды немного выросла.

In Russian past tense, the verb agrees with the subject in gender and number.

The subject here is кислотность (acidity), which is a feminine singular noun. That is why the verb is выросла.

Compare:

• кислотность выросла — the acidity increased
• уровень вырос — the level increased
• давление выросло — the pressure increased
• показатели выросли — the indicators increased

So выросла is feminine singular because it matches кислотность.

Воды is genitive because Russian often uses the noun + genitive noun pattern to mean the X of Y.

So:

• кислотность воды = the acidity of the water

This is a very common structure in Russian:

• цвет неба — the color of the sky
• температура воздуха — the temperature of the air
• уровень сахара — the sugar level

The main noun is кислотность, and воды tells us whose / of what acidity we are talking about.

No, they are related but not the same.

• кислота = acid
• кислотность = acidity, acid level, or degree of acidity

So кислотность воды means the water’s acidity, not the acid of the water.

The ending -ость often forms abstract nouns, similar to English endings like -ness or -ity:

• скорость — speed
• влажность — humidity
• плотность — density
• кислотность — acidity

Yes, literally выросла comes from вырасти, which means to grow. But in Russian, just like in English, verbs like grow, rise, and increase can be used for measurements, levels, and abstract quantities.

So Кислотность воды немного выросла naturally means:

• The acidity of the water increased a little
• The water’s acidity rose slightly

This is normal Russian usage. Other possible verbs are:

• увеличилась — increased
• повысилась — went up / increased

But выросла sounds very natural here.

Немного means a little, slightly, or somewhat here.

In this sentence it works as an adverb modifying the verb:

• немного выросла — increased a little / rose slightly

It does not change form. It is indeclinable.

Compare:

• Температура немного упала. — The temperature fell a little.
• Он немного устал. — He got a little tired.
• Добавь немного воды. — Add a little water.

In the last example, немного is closer to a little bit of. In your sentence, it is an adverb meaning slightly.

Выросла is the past tense of the perfective verb вырасти.

Russian aspect is important:

• расти = imperfective, to grow, to be growing
• вырасти = perfective, to grow / increase to a new point, to have grown

The perfective is used here because the sentence presents the increase as a completed change or a result:

• the acidity went up
• now it is at a higher level than before

If you used the imperfective, it would usually describe an ongoing process, repeated action, or background description instead.

Yes, absolutely.

Кислотность воды немного увеличилась also means The acidity of the water increased slightly and is fully natural.

There are small stylistic differences:

• выросла — rose, grew; often a bit more vivid or general
• увеличилась — increased; slightly more formal/technical
• повысилась — went up, increased; also common in technical/scientific contexts

All three can work, depending on style and context.

Yes. Russian word order is flexible, because the grammar is shown mostly by endings rather than position.

The neutral order here is:

• Кислотность воды немного выросла.

Other possible orders include:

• Немного выросла кислотность воды.
• Кислотность воды выросла немного.

These are grammatically possible, but they shift emphasis.

Very roughly:

• Кислотность воды немного выросла — neutral statement
• Немного выросла кислотность воды — emphasizes the fact of increasing
• Кислотность воды выросла немного — emphasizes a little, often contrastively

So the original version is probably the most natural default.

No, not in this sentence.

Here воды is the genitive singular of вода (water), so it means of water.

Russian воды can also be:

• nominative plural of вода in some contexts: waters
• genitive singular: of water

In кислотность воды, the meaning is clearly the acidity of the water, so it is genitive singular.

Usually either interpretation is possible, depending on context.

The sentence literally focuses on кислотность (acidity) as a measurable property, so it sounds slightly more objective or scientific than simply saying вода стала кислее.

Possible English equivalents are:

• The acidity of the water increased slightly.
• The water became slightly more acidic.

If the context is chemistry, environmental science, lab work, or water testing, Russian speakers would naturally understand it as a measurable change in acidity.

The main stresses are:

• кисло́тность
• воды́
• немно́го
• выросла́

So the sentence is pronounced approximately:

кисло́тность воды́ немно́го выросла́

A few notes:

• кислотность ends with a soft -ть
• воды́ has stress on the last syllable here
• выросла́ also has stress on the last syllable

Stress is important in Russian, so it is worth learning these as whole words.

You can say that too, and it is natural. But it means something slightly different in structure.

• Кислотность воды немного выросла — the acidity of the water increased
• Вода стала немного кислее — the water became a little more acidic / sour

The first version sounds more technical, measured, or scientific, because it talks about the property кислотность directly.

The second version sounds a bit more descriptive and less technical.

So the choice depends on style and context, not on strict correctness.