Question:
Does anyone have suggestions/recommendations/warnings aboutultra-violet water purification systems?

This is for residential use for a weekend/vacation home usingon-site well water.

The water tests ok, but the the home inspector suggested that anultroviolet purifier be retro-fitted anyway.

I will use the house only on weekends; the rest of the time thewater will just be standing in the lines.

Can UV purifiers run 24/7 even without water flowing?

How much do they cost? Are they reliable?

Answer: Things such as 'sulfur', hardness, iron, manganese, turbidity etc.have to be addressed or cleaning of the quartz sleeve has to be donemore frequently; except for turbidity, it has to be quite low. I wouldsuggest shutting off the water at the outlet of the light and pullingthe plug upon leaving.

See above. One downside to this is that you allow stagnate water tosit. Why not a shut off at the outlet of the light, nuplug it and adrain past that stop valve and drain the lines past the light whenleaving? I like the idea myself.

Depending on quality, size and features (nothing to lamp out alarmonly to intensity monitoring circuitry and solenoid valve etc.)they'll range from $400 to about $1000 installed. Beware that bulboutput intensity varies widely along with gpm sizing and only a fewhave intensity monitoring as an intrical part. Some have remote(external) monitors but most have no monitor and require annual bulbreplacement (9000 hrs continuous, two yrs noncontinuous). I suggest an8 gpm minimum. Most low end types will not have a flow control.Reliable? We'd be hardpressed to find a pharmecutical manufacturer notusing UV, along with many other users of high quality water andhundreds of thousands of regular folks. Pretreatment may be neededdepending on your water quality. A dealer that knows UV can tell youwhat to expect with a look at your water anaylsis and form amaintenance schedule for you. I have many customers without supposedpretreatment that do their maintenance and have no bacteria problems(their wells have been found to be contaminated prior to the UV lightbeing installed).