A water treatment system can reach your house in two ways: you buy it outright, or you sign a rental or lease-style agreement that bundles the equipment with a monthly or yearly payment. Both can work. The trouble starts when the homeowner assumes they bought something and the contract says otherwise. Before you sign, settle who owns the tank, what you will pay in total, and what happens when you want out.
Start with the ownership line
Find the sentence that says who owns the equipment on the day it is installed and on the day the agreement ends. Ask the provider to point to that sentence. If the contract is silent, ask for the answer in writing before you sign. Ownership decides who can repair, replace, or remove the unit, and who pays if it is damaged.
Add up the full term, not the monthly figure
Ask for the total you will have paid by the end of the agreement, counting every fee the contract mentions. Then compare that total with the upfront price of an owned system from the same provider, plus the service and supply costs you would carry yourself. Ask exactly what is included: the initial water test, installation labor, filter or media changes, salt or cartridges, and service visits. A low monthly number can leave several of these out.
Read the exit terms before you need them
Ask three questions. What is the required cancellation notice? Is there an early-termination charge, and how is it calculated? Who removes the equipment, and does the house need repairs afterward, such as patched plumbing or a relocated drain line? If the provider is responsible for removal, get the removal timing and the process in writing.
Check what happens if you sell the house
An agreement may need to transfer to the next owner, or it may end at sale with a fee. Ask whether a buyer can take over the agreement, what paperwork the seller must provide, and whether the buyout amount is fixed or changes over time. This matters more than many owners expect, because a sale happens on a schedule you do not control.
Ask what happens if the provider changes hands
Ask whether the agreement can be assigned to another company, and whether your service response terms stay the same if that happens. Ask who you call when the unit stops working and what the response window is. Get the phone number and the service-hours language into the contract itself, not just on the provider's website.
Compare the options on paper
Put the owned and leased options side by side using the same water test, the same flow rate, and the same service schedule. Write down the total cost, the exit cost, the transfer rule, and the response window for each one. If a provider will not answer these questions in writing, that refusal tells you something useful. Our method for matching systems and comparing providers explains how we set up that side-by-side comparison.