How to Get Monitoring for an Existing Alarm System
Most existing alarm panels can be monitored again if they are a common non-proprietary brand (DSC, Honeywell, GE, Bosch, Napco) and not locked with an installer code. Call the panel's company first; ADT says it can usually reactivate a working ADT system by phone. Independent companies take over panels, from $8.95 to $45 per month as of October 2026.
Figures researched 2026-10-01; each source below carries its access date. Prices change; treat any price here as "as of" its date.
Can the alarm panel in your new home be monitored?
Whether an inherited system can go live again comes down to three things you can check in about ten minutes.
- The panel brand and model. Open the metal or plastic control box (usually in a closet, basement or garage) or look at the keypad label. Independent monitoring company Alarm Relay says it can monitor the most widely installed non-proprietary systems, naming DSC, Honeywell, GE, Bosch and Napco, and that in most cases an existing system connects without replacing hardware. Panels sold by a single company for its own service only are harder to move.
- Whether the panel is locked. Alarm Grid, another company that takes over existing equipment, says some monitoring companies lock programming with a secret installer code, which can prevent another company from taking the system over. Ask the seller or the previous monitoring company for the installer code before you assume the panel is usable.
- How the panel talks to the outside world. The communicator (landline dialer, internet module or cellular radio) is the part most often swapped. Alarm Grid says that sometimes replacing only the old communicator, while keeping the panel and sensors, is enough. Our landline vs cellular monitoring guide covers which connection is worth paying for.
If the keypad shows a company name or a sticker, that company is your first call. If the system runs on a dealer platform such as Alarm.com, the Alarm.com explainer covers what changes when you switch dealers.
Who will take over an existing system, and what does it cost?
You have two routes: reactivate with the company whose name is on the panel, or hand the system to a company that monitors other companies' equipment. Published terms as of October 2026:
| Provider | What it publishes about existing systems | Monthly price | Contract |
|---|---|---|---|
| ADT | If you moved into a home with an ADT system from the previous owner, call; a working system can often be reactivated by phone | Not published for reactivations; quoted by phone | Not stated on the reactivation page |
| Brinks Home | "Extensive experience transitioning older alarm systems" | Monitoring fee starting at $29.99, plus a $6.40/mo cost recovery fee | Usually 36 months; all product purchases require a minimum 36-month monitoring contract |
| Alarm Relay | Monitors most non-proprietary panels without new hardware in most cases | $8.95 landline, $13.95 internet, $19.95 cellular | No multi-year contract; billed annually |
| Alarm Grid | Can often take over panel and sensors once the communicator is released | $15 Bronze, $25 Silver, $35 Gold (cellular), $45 Platinum | No contract, no activation fees |
Two fee details change the real price. Alarm Relay charges a $35 one-time setup fee on its landline plan and says one-time activation fees may apply to its internet and cellular plans. Brinks lists a $6.40 monthly cost recovery fee on top of the monitoring rate.
The independent route is cheaper on paper, but it only works if your panel is compatible and unlocked. The reactivation route keeps the company that already knows the equipment, at a price you will only learn on the phone. Our cheapest professional monitoring guide compares these takeover prices with DIY plans that need new hardware.
If you would rather compare quotes than make the calls yourself, our quote tool asks a few questions and fetches quotes from professional monitoring providers.
A move-in checklist for an inherited alarm
Work through this in order. Each step either gets the system online or tells you to stop and replace it.
- Ask the seller before closing. Request the master user code, the installer code if they have it, the name of the last monitoring company, and any account or contract paperwork. A previous owner's contract is theirs to close, not yours to inherit, but the paperwork tells you who to call.
- Change every user code on day one. Codes from the previous owner, cleaners and dog walkers should not carry over.
- Test before you pay. With any monitoring company, put the system in test mode and trip a door sensor so you can confirm the signal reaches the center. Sensor batteries in a system that sat idle are a common reason for a first-day trouble beep.
- Check for permit rules. Many cities require an alarm permit for monitored systems; ADT says it will obtain a permit for you where the municipality requires it and charge the permit cost plus an $8 processing fee.
- Decide by age. Alarm Grid notes that a very old panel may be worth upgrading for additional functions. If the panel is locked, proprietary or failing, compare a takeover quote against a new DIY kit.
For the rest of the move-in list (locks, garage codes, cameras), see the new home security checklist. If you are the one leaving a monitored home, moving with a security system covers the other side of this transaction.
Whether monitoring is worth paying for at all depends on how much you value a human calling for help when you cannot; that trade-off is covered in is professional monitoring worth it.
Frequently asked questions
- Can I use the previous owner's alarm system?
- Usually, if the panel works, is a common non-proprietary brand, and is not locked with an installer code. Call the company named on the keypad first; ADT, for example, says a working ADT system can often be reactivated by phone. If that company is not an option, an independent company can take over a compatible, unlocked panel.
- How much does it cost to monitor an existing alarm system?
- Independent companies publish the lowest prices: Alarm Relay lists $8.95 to $19.95 per month (billed annually) and Alarm Grid lists $15 to $45 per month for central station plans, as of October 2026. Reactivating with a national brand is quoted by phone; Brinks lists monitoring from $29.99 per month on a contract that is usually 36 months.
- What if the alarm panel is locked?
- A locked panel has an installer code set by the previous company, which can stop a new company from reprogramming it. Ask the seller or the original company for the code. If you cannot get it, the panel may need to be reset by a technician or replaced, so get a quote before buying any new sensors.
- Am I responsible for the previous owner's alarm contract?
- The previous owner's monitoring agreement is between them and their provider, so closing it is their responsibility. You start a new agreement in your name when you reactivate or switch. Read the new agreement's term before signing, since some companies require multi-year contracts.
Sources
- If you moved into a home with an ADT system from the previous homeowner, call ADT; most times, if the system is in working order, it may be reactivated by phone, and a professional will test it during the call: https://help.adt.com/article/How-do-I-reactivate-the-existing-ADT-system-in-my-home (accessed 2026-10-01)
- In municipalities that require ADT to obtain your alarm permit, ADT charges the permit amount plus a one-time $8 processing fee: https://www.adt.com/about-adt/legal/residential-terms-and-conditions (accessed 2026-10-01)
- Alarm Relay: landline $8.95/mo, internet $13.95/mo, cellular $19.95/mo, billed annually; $35 one-time setup fee on landline; activation fees may apply on internet and cellular; no multi-year contracts; monitors most non-proprietary systems including DSC, Honeywell, GE, Bosch and Napco, in most cases without replacing hardware: https://alarmrelay.com/pricing/ (accessed 2026-10-01)
- Alarm Grid central station plans: Bronze $15/mo, Silver $25/mo, Gold $35/mo (cellular), Platinum $45/mo; UL Listed central station: https://www.alarmgrid.com/monitoring (accessed 2026-10-01)
- Alarm Grid: no contracts and no activation fees: https://www.alarmgrid.com/ (accessed 2026-10-01)
- Alarm Grid can often take over a system once its communicator is released, or replace only the communicator; proprietary equipment and secret installer codes can prevent takeover; very old panels may warrant an upgrade: https://www.alarmgrid.com/blog/bring-your-existing-monitoring-equipment-to-alarm-grid (accessed 2026-10-01)
- Brinks Home: extensive experience transitioning older alarm systems to its monitoring service: https://brinkshome.com/faqs (accessed 2026-10-01)
- Brinks Home monitoring fee starting at $29.99/mo; cost recovery fee $6.40/mo; monitoring plan is a contract usually 36 months: https://brinkshome.com/help-center/articles/Understanding_Your_BrinksHome_Fees (accessed 2026-10-01)
- Brinks Home: all product purchases require acceptance of a minimum 36-month monitoring contract: https://brinkshome.com/terms (accessed 2026-10-01)
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