Stuur het taxatierapport, tenzij de gemeente het al heeft.

Because Stuur is an imperative: a command or instruction.

• Stuur = Send
• The subject you is understood and usually not stated.

So:

• Stuur het taxatierapport = Send the valuation report

If you did include the subject, it would sound less like a direct instruction and more marked, for example:

• Stuur jij het taxatierapport.
  This can sound emphatic or unusual depending on context.

Tenzij means unless.

It introduces an exception to what is said in the main clause:

• Stuur het taxatierapport = Send the valuation report
• tenzij de gemeente het al heeft = unless the municipality already has it

A useful way to think about it:

• Do X, unless Y is true.

In Dutch, tenzij is a subordinating conjunction, and that affects word order in the clause that follows it.

Because the clause after tenzij is a subordinate clause.

In Dutch subordinate clauses, the conjugated verb usually goes to the end:

• tenzij de gemeente het al heeft

Compare that with a main clause:

• De gemeente heeft het al.

So:

• main clause: subject + verb + rest
• subordinate clause: subject + rest + verb

That is one of the most important word-order patterns in Dutch.

The two instances of het do different jobs.

1. het in het taxatierapport is the definite article

   • het taxatierapport = the valuation report

2. het in de gemeente het al heeft is a pronoun

   • here it means it, referring back to het taxatierapport

So the sentence is structurally:

• Send [the valuation report], unless the municipality already has [it].

This is very common in Dutch.

Because rapport is a het-word, and the compound noun keeps that gender.

• het rapport
• therefore: het taxatierapport

In Dutch compound nouns, the last part usually determines the gender and article.

So:

• taxatie = valuation/appraisal
• rapport = report
• taxatierapport = valuation report

Since rapport takes het, the whole compound does too.

Here al means already.

So:

• de gemeente het al heeft = the municipality already has it

Dutch al is very commonly used where English uses already.

In this sentence, al comes before the final verb because the clause is subordinate:

• main clause: De gemeente heeft het al.
• subordinate clause: ... tenzij de gemeente het al heeft.

Because Dutch has preferred positions for objects and adverbs.

In this clause:

• de gemeente = subject
• het = object pronoun
• al = adverb
• heeft = verb

A very natural order is:

• subject + object pronoun + adverb + verb

So:

• de gemeente het al heeft

Putting al before het would sound unnatural here.

A good learner pattern to remember is:

• ... dat hij het al weet
• ... omdat ze hem nog kent
• ... tenzij de gemeente het al heeft

Yes, that is grammatically possible, but it is less natural in this context.

Why?

Because once het taxatierapport has already been mentioned in the main clause, Dutch normally prefers to replace it with the pronoun het in the subordinate clause:

• more natural: tenzij de gemeente het al heeft
• less compact/repetitive: tenzij de gemeente al het taxatierapport heeft

Using the pronoun avoids repeating the full noun phrase.

Because tenzij de gemeente het al heeft is a subordinate clause added after the main clause.

Dutch often uses a comma before subordinate clauses introduced by words like:

• omdat = because
• als = if/when
• terwijl = while
• tenzij = unless

So the comma here is standard and helps show the break between:

• Stuur het taxatierapport
• tenzij de gemeente het al heeft

Because Dutch often uses the present tense in exactly the same kind of situation as English:

• unless the municipality already has it

The sentence is giving an instruction about a present or relevant condition. It does not need a future form.

Dutch often uses the present tense where English also uses the present:

• Bel me als je tijd hebt. = Call me if you have time.
• Stuur het rapport tenzij zij het al heeft. = Send the report unless she already has it.

Yes. Gemeente often means municipality, but depending on context it can also be understood more loosely as:

• the local authority
• the council
• the municipal administration

So in practical translation, the best English choice depends on context. Grammatically, though, de gemeente is simply the subject of the subordinate clause.

Yes. Dutch very often forms long compound nouns by joining words together.

Here:

• taxatie = valuation/appraisal
• rapport = report
• taxatierapport = valuation report

English often uses separate words where Dutch prefers one compound word.

Other examples:

• huisdeur = house door / front door
• zorgverzekering = health insurance
• gemeentehuis = town hall

So taxatierapport may look long, but for Dutch it is a very normal structure.

Yes. For example:

• Je stuurt het taxatierapport, tenzij de gemeente het al heeft.

That means something like:

• You send the valuation report, unless the municipality already has it.

This helps show the underlying grammar:

• main clause: Je stuurt het taxatierapport
• subordinate clause: tenzij de gemeente het al heeft

The original sentence just changes the main clause into the imperative:

• Stuur het taxatierapport