higaerinyuuyoku no nyuutouzei, gensen, sensitu, kounou wo kakuninsita.

A simple way to break it down is:

• 日帰り入浴の = for day-use bathing / regarding a day trip bath visit
• 入湯税、源泉、泉質、効能 = bath tax, spring source, spring quality, medicinal effects
• を確認した = checked / confirmed

So the basic structure is:

[topic/category] の [list of things] を 確認した

In other words:

I checked the day-use bathing information: the bathing tax, source spring, spring quality, and effects.

The core verb is 確認した, and everything before を is what was checked.

日帰り入浴 is read ひがえりにゅうよく.

It is made of:

• 日帰り = a same-day trip, not staying overnight
• 入浴 = bathing

Together, 日帰り入浴 means something like:

• day-use bathing
• a same-day hot spring bath visit
• bathing without an overnight stay

This is common in hot spring, spa, or onsen contexts. It refers to using the bath facilities for the day rather than booking a room and staying overnight.

Here, の links 日帰り入浴 to the nouns that follow it.

So:

• 日帰り入浴の入湯税 = the bathing tax for day-use bathing
• 日帰り入浴の源泉 = the spring source for the day-use bath
• 日帰り入浴の泉質 = the water quality/type for the day-use bath
• 日帰り入浴の効能 = the benefits/effects for the day-use bath

In English, の often becomes:

• of
• for
• a possessive-like relationship
• a descriptive link

Here, for or regarding sounds more natural than a literal of.

Because all four nouns are part of one list, and the whole list is the object of 確認した.

So:

• 入湯税、源泉、泉質、効能 = one combined object list
• を確認した = checked them

Japanese often puts one particle after the entire list instead of repeating it after each item.

So this works like:

• A, B, C, and D を確認した

not:

• Aを、Bを、Cを、Dを確認した

The repeated version is possible in some contexts, but it is less natural here.

The commas are being used to list items in a compact way.

So:

• 入湯税、源泉、泉質、効能 = bath tax, spring source, spring quality, and effects

Japanese often uses 、 to make a straightforward list, especially in:

• notes
• reviews
• informational writing
• websites
• brochures

If you used と, it would sound more explicitly like A and B and C and D:

• 入湯税と源泉と泉質と効能を確認した

That is grammatical, but the comma list is more concise and natural for this kind of informational statement.

Here are the readings:

• 入湯税 = にゅうとうぜい
• 源泉 = げんせん
• 泉質 = せんしつ
• 効能 = こうのう

A few notes:

• 入湯税 is a special tax charged at hot spring areas.
• 源泉 means the source spring itself, the original spring water source.
• 泉質 means the quality/type of the hot spring water, such as sulfuric, alkaline, etc.
• 効能 means the claimed benefits or therapeutic effects of the hot spring.

Yes, they are related, but they refer to different things.

• 源泉 = the source of the hot spring water
  This is about where the water comes from.

• 泉質 = the quality/type/composition of the spring water
  This is about what kind of water it is.

So, for example:

• 源泉 answers a question like: What spring is this bath using?
• 泉質 answers a question like: What kind of hot spring water is it?

A useful comparison:

• 源泉 = source
• 泉質 = water type / mineral quality

確認した is the past plain form of 確認する, which means:

• to confirm
• to check
• to verify

It often sounds a little more deliberate than simply looked at.

So 確認した suggests the speaker intentionally checked this information.

Depending on context, it could mean:

• I checked
• I confirmed
• I verified

Because this sentence sounds informational, checked or confirmed is usually the best translation.

Japanese often omits the subject when it is clear from context.

So this sentence does not explicitly say:

• I checked
• we checked
• someone checked

But in natural translation, it will often become I checked if the speaker is talking about their own action.

This is very common in Japanese. If the subject is obvious or unimportant, it is simply left out.

It is understandable as a normal sentence, but it does have a slightly concise, note-like feel.

That is because:

• it lists several informational items
• it ends with a straightforward past verb
• there is no extra context or subject

So it could sound like something from:

• a travel memo
• a review
• a blog note
• a checklist before visiting an onsen

In more expanded everyday speech, someone might say something like:

• 日帰り入浴について、入湯税や源泉、泉質、効能を確認した。
• 日帰り入浴の情報として、入湯税、源泉、泉質、効能を確認した。

But the original is still perfectly understandable.

No. In normal Japanese, this would usually be written without spaces:

日帰り入浴の入湯税、源泉、泉質、効能を確認した。

Spaces are sometimes added in teaching materials to make reading easier, but standard Japanese writing normally does not separate words with spaces the way English does.

So if you saw this in a real text, it would usually appear as one continuous string with punctuation.