We will install HO supplied materials, but we offer no warranty on them.
However, we prefer to supply our own materials for two reasons.
1. Customer supplied materials usually take longer to install - especially when dealing with plastic parts / pieces. We lose money when we give a price upfront. The install always appears easy enough until you start working with a defective, cheaply constructed faucet. All put together, clean up, one last check, and then drip . drip.
2. When we get call backs, customers have a hard time believing it is what they supplied. They think somehow you installed it wrong. The faucet will work for two months and then drip . drip . drip
Depending on the customer, we have gone back and tightened for no charge. At some point, we will draw a line in the sand and either refuse to install junk or refuse to go back for free.