Влажное пятно — под гибкой подводкой, рядом с запорным краном.

This is a very common Russian pattern, especially in descriptions, notes, reports, and inspections.

Russian often leaves out the verb to be in the present tense. So instead of saying:

• Влажное пятно находится под гибкой подводкой...

it can simply say:

• Влажное пятно — под гибкой подводкой...

The dash helps separate:

• the thing being identified: влажное пятно
• its location: под гибкой подводкой, рядом с запорным краном

This makes the sentence sound concise and matter-of-fact, which fits technical or inspection-style language very well.

Here подводкой is in the instrumental case.

That is because the preposition под can take two different cases:

• accusative for movement to a position: положить под стол = to put under the table
• instrumental for location: лежать под столом = to lie under the table

In this sentence, the wet spot is already located there, so it is location, not movement:

• под гибкой подводкой = under the flexible supply hose/line

The adjective also matches the noun in instrumental feminine singular:

• гибкая подводка
• под гибкой подводкой

Рядом с means next to / beside, and it requires the instrumental case.

So:

• запорный кран becomes с запорным краном

The adjective changes too:

• запорный → запорным

So the whole phrase means:

• рядом с запорным краном = next to the shutoff valve

This is a good phrase to memorize as a unit:

• рядом с + instrumental

In everyday plumbing Russian, гибкая подводка usually means a flexible water supply hose/connector.

Literally:

• гибкая = flexible
• подводка = something like supply line/connection feed

In plumbing, it often refers to the short braided hose that connects a faucet, toilet, or appliance to the water supply.

So in this sentence, под гибкой подводкой most likely means:

• under the flexible supply hose
• or under the flexible connector

Not exactly.

• кран can mean tap, faucet, or valve, depending on context.
• запорный кран is more specific: it means a shutoff valve or stop valve.

The adjective запорный comes from the idea of shutting off / blocking flow.

So:

• кран = general word
• запорный кран = a valve specifically used to stop the water flow

This kind of phrase is common in maintenance, repair, and inspection language.

Both words relate to wetness, but they are not exactly the same.

• влажный = damp, moist
• мокрый = wet, soaked

So влажное пятно suggests a damp patch / moist spot, which is often a natural choice when describing a suspicious area near plumbing.

If you said мокрое пятно, it would sound wetter or more obviously soaked.

In technical or observational language, влажное пятно can sound a bit more neutral and precise.

Пятно literally means spot, patch, or stain.

In this context, it does not necessarily mean a colored stain. It refers to a visible wet patch or damp area.

So here it is best understood as:

• a damp spot
• a wet patch
• a moisture mark

It describes what someone sees, not necessarily the cause. The sentence points out the location of the wet area, but it does not directly say there is a leak.

Yes. Russian word order is flexible, especially in descriptive sentences like this one.

For example, you could also say:

• Под гибкой подводкой, рядом с запорным краном — влажное пятно.

This puts the location first and the item second, which can sound like:

• Under the flexible hose, next to the shutoff valve, there is a damp spot.

The original version starts with влажное пятно, which makes the damp spot the main topic right away.

So the word order affects emphasis more than basic meaning.

Yes, in many situations you could use another nearby-location expression, but the grammar would change.

For example:

• рядом с запорным краном = next to the shutoff valve
• возле запорного крана = near/by the shutoff valve

Important difference:

• рядом с takes instrumental
• возле takes genitive

So:

• рядом с запорным краном
• возле запорного крана

The meaning is similar, though рядом с can feel a bit more like right next to, while возле can be slightly broader, like near or by.

It is grammatically fine, but it sounds like a brief descriptive note, not like conversational everyday speech.

This style is very natural in:

• maintenance reports
• inspection notes
• repair descriptions
• damage assessments

A fuller spoken version might be:

• Влажное пятно находится под гибкой подводкой, рядом с запорным краном.

But the shorter version is efficient and perfectly natural in written technical context.

The adjectives agree with their nouns in gender, number, and case.

Here is the breakdown:

• влажное пятно

  • пятно is neuter singular nominative
  • so влажное is neuter singular nominative

• под гибкой подводкой

  • подводка is feminine singular
  • after под in a location meaning, it becomes instrumental singular: подводкой
  • so the adjective also becomes instrumental singular feminine: гибкой

• рядом с запорным краном

  • кран is masculine singular
  • after рядом с, it becomes instrumental singular: краном
  • so the adjective becomes instrumental singular masculine: запорным

So each adjective is simply matching the noun it describes.