A bomba d'água funciona desde segunda-feira.

d'água is a contracted form of de água. The apostrophe shows that the e in de has been dropped before the vowel in água.

In modern Portuguese, this kind of spelling is mostly kept in a number of established expressions and compound nouns, such as:

• bomba d'água
• caixa-d'água
• olho-d'água

So in this sentence, bomba d'água is best learned as a set expression.

By itself, bomba can mean bomb, but it can also mean pump. In bomba d'água, it means water pump.

This is very common in Portuguese: the exact meaning depends on the context or on the full expression.

Yes. Bomba d'água is a very common set phrase in Brazilian Portuguese for a water pump.

Even though de água would be understandable in other contexts, bomba d'água is the usual established form for this noun.

A is the feminine singular definite article, meaning the.

It is used because bomba is a feminine singular noun:

• a bomba
• uma bomba

So A bomba d'água means the water pump.

Portuguese often uses the simple present with desde to express something that started in the past and is still true now.

So:

• A bomba d'água funciona desde segunda-feira.

can naturally mean:

• The water pump has been working since Monday.

This is normal Portuguese usage. English often prefers the present perfect progressive, but Portuguese does not have to match that structure directly.

Yes. That is also natural.

The difference is mostly one of emphasis:

• funciona sounds more neutral or factual
• está funcionando emphasizes the ongoing activity or current functioning

Both can work in everyday Brazilian Portuguese.

Here, desde means since.

It marks the starting point of an action or state that continues up to the present:

• desde segunda-feira = since Monday

It can also mean from, depending on context, but in this sentence since is the best match.

The names of weekdays from Monday to Friday are traditionally written with -feira and a hyphen:

• segunda-feira
• terça-feira
• quarta-feira
• quinta-feira
• sexta-feira

This is just the standard spelling.

In casual speech, Brazilians often shorten them:

• segunda
• terça
• quarta

But in full form, the hyphen is standard.

In Portuguese, days of the week are normally written in lowercase, not with capitals.

So you write:

• segunda-feira
• terça-feira
• janeiro
• brasileiro

This is different from English, where Monday is capitalized.

After desde, it is very common to say:

• desde segunda-feira

without an article.

This simply means since Monday.

You may also hear desde a segunda-feira in some contexts, but the version without the article is very common and natural here.

Because the subject is singular: A bomba d'água.

So the verb must also be singular:

• A bomba d'água funciona
• As bombas d'água funcionam

The ending -a in funciona matches ele/ela/você in the present tense.

In normal Brazilian pronunciation, d'água is said almost like dágua, with no clear e sound from de.

A rough English-friendly approximation would be:

• DAH-gwah

But the real Portuguese pronunciation is smoother and more connected.

Also, the accent mark in água shows the stress falls on the first syllable:

• Á-gua