Nettleien står på en annen regning.

Because nettleien is the definite singular form of nettleie.

• ei/en nettleie = a grid fee / network charge
• nettleien = the grid fee / the network charge

In Norwegian, definiteness is often added as an ending on the noun instead of using a separate word like the.

Because Norwegian usually puts the into the noun itself.

So instead of saying something like the nettleie, Norwegian says:

• nettleien = the grid fee

This is very normal in Norwegian:

• en bil = a car
• bilen = the car

Yes, literally står på means stands on, but here it is idiomatic.

In this sentence, står på en annen regning means something like:

• is listed on another bill
• appears on another invoice
• is shown on a separate bill

Norwegian often uses stå in this way for text or information that appears somewhere:

• Det står på nettsiden. = It says so on the website.
• Navnet ditt står på listen. = Your name is on the list.

So this is a very useful expression.

Because Norwegian usually uses på when something is written on a page, bill, list, website, sign, and so on.

Examples:

• på regningen = on the bill
• på listen = on the list
• på skjermen = on the screen
• på nettsiden = on the website

So står på en annen regning is the natural choice.

Because annen means another or a different one.

Here, the sentence means the fee appears on another / a different bill, so annen is correct.

Compare:

• en annen regning = another bill / a different bill
• den andre regningen = the other bill / the second bill

So:

• annen = another, different
• andre often appears in plural or in expressions like den andre = the other one / the second one

They are close in meaning, but there is a small nuance:

• regning = bill, everyday word
• faktura = invoice, more formal/business-like

In many situations, both can work. In everyday speech, regning is very common. In official or business contexts, faktura may sound more precise.

So Nettleien står på en annen regning sounds natural and everyday.

Yes, you probably could, and people would understand you. But står på is more idiomatic when talking about information that is written somewhere.

Compare:

• Nettleien står på en annen regning. = The grid fee is listed on another bill.
• Nettleien er på en annen regning. = The grid fee is on another bill.

The version with står på sounds a bit more natural when referring to text or charges shown on a document.

Yes. It is a compound noun:

• nett = grid/network
• leie = fee/rent/charge

Together, nettleie refers to the charge for using the electricity grid. This kind of compound noun is extremely common in Norwegian.

Other examples:

• strømregning = electricity bill
• mobilregning = phone bill
• nettbutikk = online store

Regning is feminine in many varieties of Norwegian, but it is often treated as a common-gender noun in Bokmål.

That is why you see:

• en regning = a bill
• en annen regning = another bill

In Bokmål, many feminine nouns can take en instead of ei, especially in standard written usage.

So you may also encounter:

• ei regning

But en regning is completely normal.

No, this is normal Norwegian statement word order:

• Nettleien = subject
• står = verb
• på en annen regning = prepositional phrase

So the pattern is basically:

Subject + verb + rest

This is the standard order in a simple main clause:

• Boken ligger på bordet.
• Navnet står på listen.
• Nettleien står på en annen regning.

It can mean both, depending on context.

So en annen regning can mean:

• another bill
• a different bill

In this sentence, both ideas fit well: the fee is not on this bill, but on a separate/different one. That is why annen is a very natural choice here.