Is it ok to take diurex water pill (caffeine free) with lisonipril?

Yes: Yes. It is ok to take Lisinopril while you take diurex.

Using diurex?: Before you take diurex (d), discuss it with your physician (p). Your blood pressure may be well controlled on Lisinopril (l). If it is, you need not take d. If not, perhaps you p could increase your dose of l to its maximum. It is rarely a good idea to take any medicine to lower your BP without your p's knowledge and consent.