UV Disinfection
Ultraviolet Disinfection for Private Well Water
UV is the right answer to a specific problem and the wrong answer to several others. This page is about telling them apart.
How UV works
Water passes a lamp inside a quartz sleeve; ultraviolet light disrupts the organisms' DNA so they can't reproduce. No chemical goes into the water and nothing changes the taste.
What UV does not do
- •It leaves no residual. Water is treated only at the point it passes the lamp. Bacteria already living downstream in the plumbing or in a storage tank are not touched. This is why we shock-chlorinate the system before a UV system goes in rather than after.
- •It does not remove anything. Nitrate, arsenic, iron, manganese, hardness and gross alpha pass straight through.
- •It does not work properly in water that isn't clear. Turbidity, sediment, iron, manganese and hardness coat the quartz sleeve and shadow the organisms from the light. A fouled sleeve can leave a system that looks like it's running and isn't treating anything.
- •It does not find the reason bacteria are getting into your well. See our well water chlorination page.
What UV needs upstream
Sediment filtration, and iron, manganese and hardness dealt with before the lamp rather than after. A UV system installed on untreated iron-bearing water is a maintenance problem waiting to happen.
Maintenance — the part people don't get told
The lamp loses output long before it stops lighting up, so it is replaced on a schedule, not when it fails. The sleeve needs cleaning. Many systems have an alarm or a solenoid that shuts flow on failure, and if yours doesn't, you have no way of knowing it has stopped working. That's a reason to know what you have.
UV versus continuous chlorination
UV: no chemical, no taste, no residual, needs clear water, needs lamp changes. Continuous chlorine: works in water UV can't handle, gives a residual through the plumbing, needs a contact tank and a chemical supply, and can affect taste. Neither is universally better — the right one depends on the water and the problem.
Drilling a new well and sealing an old one are a different licence — a licensed well driller — and we don't do that work. See our NJ pump installer licence page.
Straight answers
Questions we get on this one
Does UV change the taste?
No. Nothing chemical goes into the water and nothing is added or removed, so the taste doesn't change. If your taste changed after a UV unit went in, something else in the system did it.
What happens in a power outage?
The lamp stops, and untreated water can pass through. Many systems have a solenoid that shuts flow on power loss or lamp failure; if yours doesn't, you have no way of knowing it stopped treating. That's a reason to know what you have.
How often does the lamp get replaced?
On a schedule, not when it fails. The lamp loses output long before it stops lighting up, so it's replaced at the manufacturer's interval — typically annually — regardless of whether it still glows.
Can UV replace boiling during a boil advisory?
A properly sized and maintained UV system inactivates bacteria at the point of entry. Whether it satisfies a specific boil advisory depends on the advisory and the organism, so follow the health department's guidance for the situation in front of you.
Do I still need to test my water if I have UV?
Yes. A UV system only works if the lamp is good, the sleeve is clean, and the water reaching it is clear enough. Testing is how you confirm the system is actually treating — and NJDEP's own advice is to retest after any treatment system goes in.
Will UV help with the smell?
No. UV does not remove anything — not iron, not manganese, not the sulfur compounds behind a rotten-egg smell. If the smell is the problem, UV is the wrong tool, and the cause needs a different treatment.
We answer around the clock
No water? Call. Don't type.
(862) 276-0328No water right now? Call (862) 276-0328.
Or request service online — but if you're standing in a dark basement with no water, the phone is faster.