Marble is not among the manufacturer-listed surfaces, and the product’s chemistry and pH are undisclosed. Marble can be sensitive to unsuitable cleaners, especially when unsealed or polished.
Why
Zep approves ceramic, porcelain, granite, quartz tile, and sealed grout, but provides no evidence specifically supporting marble compatibility. The unknown chemistry creates a realistic unresolved risk.
What to do
Do not use on marble unless Zep confirms compatibility. If confirmed for a particular sealed marble surface, follow the label method and spot-test first.
pH
Not disclosed in retrieved manufacturer evidence.
Relevant chemistry
No named chemistry or pH was shown in the retrieved manufacturer evidence.
Source: official product page ↗