Learn Hardcore Italian: Prendo il secchio e lo riempio d’acqua, poi bagno lo straccio. - I take the bucket and fill it with water, then wet the rag.

It’s the direct object pronoun meaning "it," referring back to il secchio (the bucket). You use lo because secchio is masculine singular. So: Prendo il secchio e lo riempio (d’acqua) = I take the bucket and fill it.

Feminine singular would be la: Prendo la bacinella e la riempio.
Plural masculine: li; plural feminine: le.

Why is it "d’acqua" and not "con acqua"?

With verbs like riempire, Italian normally uses di to express the content: you fill something "of" a substance: riempire d’acqua, d’aria, di sabbia.

Con can also appear, but it’s less idiomatic for contents and is more common when emphasizing the means/source or contrasting options: riempire la vasca con acqua piovana. In everyday Italian, prefer riempire d’acqua.

What’s the difference between the "lo" in "lo riempio" and the "lo" in "lo straccio"?

Two different words:

lo in lo riempio = direct object pronoun "it."
lo in lo straccio = the masculine singular definite article "the," used before words starting with s + consonant (s impura), z, gn, ps, x, y (e.g., lo zaino, lo psicologo, lo gnocco).

Do I need an article before "acqua"? Is "dell’acqua" possible?

In this set phrase, d’acqua (di + acqua) is the most natural and common. You may see dell’acqua (partitive "some water") or con dell’acqua, but here they’re less idiomatic. Stick with d’acqua after riempire when stating what the container is filled with.

Is "riempio" one of those -ire verbs that take -isc?

No. Riempire is a regular -ire verb without the -isc insertion. Present tense:

io riempio
tu riempi
lui/lei riempie
noi riempiamo
voi riempite
loro riempiono

Where does the object pronoun go? Could I say "riempio lo"?

Clitic object pronouns normally go before the conjugated verb: lo riempio (not ✗ riempio lo). They can attach to infinitives, gerunds, and imperatives:

infinitive: riempirlo d’acqua
imperative: riempilo d’acqua
gerund: riempiendolo d’acqua

Why not "gli riempio" if "secchio" is masculine?

Because gli is (mainly) an indirect object pronoun meaning "to him/for him" (and in modern usage often "to them"). The thing being filled (the bucket) is a direct object, so you need lo. You can say: Gli riempio il bicchiere = I fill his glass (gli = to him; il bicchiere = direct object).

Could I drop the pronoun and repeat the noun? "Prendo il secchio e riempio il secchio."

It’s grammatical but sounds clunky and repetitive. Italian prefers a pronoun to avoid repetition: Prendo il secchio e lo riempio.

Is the comma before "poi" necessary?

It’s optional and reflects a natural pause. Both are fine:

… d’acqua, poi bagno lo straccio.
… d’acqua poi bagno lo straccio. Writers often use the comma to separate steps in a sequence.

Does "poi" mean the same as "allora"?

Not exactly. Poi marks sequence ("then/after that"). Allora can mean "then" in a more logical or discursive sense, and it’s also a common filler ("so, well"). In instructions or narration of steps, poi is the default.

Why is it "lo straccio" and not "il straccio"?

Because straccio starts with s + consonant. Masculine singular nouns of that type take lo (and the indefinite uno): lo straccio, uno straccio. Compare: il secchio, un secchio (no s + consonant, so regular il/un).

What’s the difference between "bagno lo straccio" and "mi bagno"?

Bagno lo straccio = I wet the rag (transitive; you act on something else).
Mi bagno = I get (myself) wet (reflexive; the subject undergoes the action). If you wanted to say the rag gets wet by itself: lo straccio si bagna (less likely here).

How would I say the whole thing in the past?

Perfective past (passato prossimo):

Ho preso il secchio e l’ho riempito d’acqua, poi ho bagnato lo straccio. Note the past participle agreement with a preceding direct object pronoun:
la bacinella? L’ho riempita d’acqua.
il secchio? L’ho riempito d’acqua.

Could I also pronominalize "lo straccio" as "poi lo bagno"?

Grammatically yes, but it may be ambiguous since lo just referred to il secchio. To avoid confusion, keep the noun or add clarity:

… lo riempio d’acqua; poi bagno lo straccio.
Or: … lo riempio d’acqua; poi lo bagno, cioè lo straccio. (still a bit clunky) Clarity usually wins: repeat lo straccio.

Why is there an apostrophe in "d’acqua"?

It’s elision: di becomes d’ before a vowel to ease pronunciation. Same idea with l’acqua (from la acqua → l’acqua).

Any pronunciation tips for tricky words here?

riempio: roughly "ree-EM-pyo" (stress on EM; the group -empio sounds like -em-pyo).
straccio: "STRAH-cho" (the "cc" before i/e yields a "ch" as in "church," then "o").
secchio: "SEK-kyo" (double c + h = hard k; "chio" sounds like "kyo").
bagno: "BAHN-nyo" (the "gn" is like Spanish ñ).
acqua: "AHK-kwa" (double c + q = strong k sound).

Is "e" ever written as "ed" in this sentence?

No, because lo starts with a consonant. Ed is an optional variant of e used mainly before words beginning with a vowel (especially e) to improve flow: ed è, ed io. Here, e lo riempio is correct and natural.