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CoSine Real Estate Our full service San Diego property management is a comprehensive package of management solutions to ensure your properties operate smoothly, increase in desirability and enhance in value. Aggressive and efficient marketing ensures we consistently and quickly secure well qualified tenants. Our dedicated maintenance department and strong vendor relationships provide honest, quality work.

Our professional, full service property management covers every aspect of your investment. From the first tenant to the last, a tiny leak to the largest flood, we have you covered.
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CoSine Property Management is a San Diego based property management firm that provides comprehensive, professional property management. We are committed to enhancing asset value and providing our clients with the information they need to fully maximize the financial potential of their rental properties.
We offer a full range of property management services tailored to you as an investor, homeowner, or landlord. We have an extensive portfolio with over 300 single family homes, townhouses, condos, and apartment buildings in San Diego. Whether you own one rental or a dozen, you will receive professional, full-service management to ensure your properties operate smoothly and increase in value.
Log in to the Buildium portal to see reports, track expenses and revenues, download documents, and find information about your properties. Rest assured evictions with us are very rare. In over 12 years managing over 300 properties we have had less than 6 evictions. That's incredible and due in large part to our extreme vetting.
We understand life happens and sometimes it becomes necessary to break a lease. Tenants are responsible for all rents until the lease expires or we find new tenants. We work with you to aggressively market and show the rental to minimize any vacancy time (and save you money). Contact your Property Manager for more details.
Reviews (22)
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Kaitie W.
Feb 09, 2022
This real estate company is awful. We tried to reach them for two weeks after applying right away and touring a house we really wanted to rented. Not one person ever got back to us. It took me searching through their website to find a direct contact. Even after speaking with the direct contact that person apologized but didn't do anything to help us in any ways.

End of the story we didn't even get our application looked at by the owners and we didn't get the house after TWO WEEKS almost three of trying to get a hold of someone. I was then told a supervisor would be in contact with me shortly. Still have yet to hear from someone. If you see a rental from them don't plan on hearing from them unless you work with Martha she is the only person that ever got a hold us us after the two week time period.
Bob Davis
Jan 30, 2022
Jeremy is a consummate professional. His dedication to his clients is 2nd to non in San Diego. I have worked with a few other property managers that did little more than process my rents. Jeremy is highly focused on communicating and keeping me in the loop about all goings on with my property. Cannot recommend him enough.
Lex Gonzalez
Dec 26, 2021
Scheduled a viewing to look at a place they had for rent. Very unprofessional company. They were texting me all weekend to confirm my appointment which I did and they texted me a reminder of the time of the viewing. Got to the place 10 min. Early and nobody was there so I waited patiently for my scheduled time. After 5 min pass I call the agent and text no answer.

I waited there for almost 30 min they NEVER showed up! No text back or call backs from them and never got to see the place. Waisted my time but I'm glad because I would never want to rent from a company like that anyways.
Tony V.
Apr 29, 2021
I've seen some of the reviews on here and I'm a little surprised because I honestly never had a problem with cosine in the time I rented from them. I lived in my home for 2 years and from the rental process to the move out process, it couldn't have been any easier. Setting up a tour was easy and my family and I were able to start the rental process not much longer after viewing the house.

In the time we lived there, we only ever had to reach out to cosine for 2 things needing assistance, and both times they quickly connected us with a maintenance guy so we could schedule an appointment that fit our schedule. When we notified them that we were moving out, they were prompt to reply and didn't harass us to leave early or anything.

The moving out day, Jeremy stopped by and we did a quick walk through. I still hadn't showered after moving out the last few things and asked Jeremy if I could take a quick shower before leaving the house. He said that was no problem and just told me to lock up on my way out and leave my key. That was really nice of him to let me do that. After moving out, a week later, Jeremy reached out to ask me for my mailing address to send me our deposit refund.

We received a check for the entire deposit just a few days later in the mail and cashed it without a hitch. Top notch service from Jeremy and his crew at Cosine Management, I highly recommend them if you're in search of a nice place to rent that you can call home.
Yelp C.
Feb 01, 2021
As an owner, cosine has been amazing. If you read the negative they are mostly from tenants. Martha and Jeremy have been amazing and a pleasure to work with. They are very professional.
Elidia V.
Jul 10, 2020
My roommates and I saw a townhouse for rent and immediately contacted the property management to view it. We were told that it would not be available for viewing for about a week and we asked if we could fill out the application and rent the home unseen as we loved the location so much. We were told that they had rules about renting they would not run the application without us viewing the home.

We thought this was an OK plan because we already had applications filled out and we just had to view the home to check all of their boxes. The day before the viewing we receive a confirmation text message that we were scheduled to see the home. My roommates traveled over an hour, took the day off of work and we showed up to the viewing almost 30 minutes early and saw the home.

We all agreed that we loved the house and gave Nicole a call immediately to let her know we wanted to move forward with our applications She calls us back about an hour later and tells us that she's already approved someone else's applications and was working on their lease this morning. It is extremely frustrating to know that this was not a timing issue or a scheduling issue, it was pure and simply a lack of consideration for someone else's time.

If you're working on someone else's lease and putting the finishing touches on it that morning why would you not call us and tell us this so that we could've saved our time and money in visiting this place. This really shows a lack and professionalism. I understand that homes go quickly but I'm shocked that this company did not even do the bare minimum which would've been a quick email.
Joshua P.
Jul 03, 2020
Scheduled an appointment for a a tour and as soon as I arrived at the property they canceled. I confirmed through email and telephone and they still weren't accountable to their appointment. When I called they said it was a computer error and they apologize. It's really frustrating when a company doesn't value your time and they ask you to respect theirs at the same time. Hypocritical and selfish. -Other places don't schedule appointments when there is a pending applicant.

It seems to me that you were willing to risk my time instead of your own so that you could have more applicants in your pool ready to move. I know business is tough but you can't cut corners and expect everyone to be ok with it. You spent more than an hour of my life on something that could have been avoided and your trying to say that you respect my time. I made the appointment less than 24 hours before the so you must have already had that applicant pending.
George P.
May 04, 2020
Absolutely terrible. The worst communication, unprofessional. I'm surprised this is a functioning company
Kevin James
Mar 11, 2019
I rented a unit from Cosine real estate and it was really simple. I called them up, got an application, went and view the property with the agent and got the keys a few days later. I leased the unit for 12 months and only had 1 issue with the dishwasher that was handled pretty fast. When I was ready to buy a house about a year later, the owner Jeremy personally handled my buying transaction. Great service overall.
Peggy W.
Feb 24, 2019
I've lived in a condo (single unit in a larger building) managed by CoSine for nearly 1 1/2 years. So far everything has been great. Martha, Jenny, Jessica (HOA) and Jeremy have been prompt in responding to any issues that might arise. I have two dogs, a Lab, and a Ridgeback. CoSine is good about alerting me ahead of time when anyone might have to come in to service the AC/Heating unit or whatever else might require entrance into my home.

I feel fortunate to have found the perfect place to live upon arriving in San Diego. And for me, CoSine has been instrumental in making my move even more enjoyable. I'm not disavowing anyone else's comments. I can only share my personal experience and wish everyone else the same!
Patricia Teichert
Feb 11, 2019
A gas leak was discovered on March 8, 2019 at the house I am renting. It is now April 8, 2019. An entire month has passed. I have been having to take cold showers and no laundry this entire time. Jeremy and Martha have been doing nothing but giving us the run around. He does not respond to emails nor texts. The incompetence of this company is beyond belief.

They do not follow through with progress or lack thereof. DO NOT RENT ANYTHING FROM THIS COMPANY. I've been trying to get the property owners name and number to let them know they are getting screwed over by this company. There simply is no excuse for this.
Robert Davis
Nov 11, 2018
Rented a house for a couple years through cosine. only talked with them one time, everything else was done online and super easy. Maintenance issues where always handled in a reasonable amount of time. I like they way they do business. Would rent from them again.
Amy B.
May 25, 2018
I rented through Cosine and they wanted me to leave a few days before my lease expired so a new tenant could move in. I was fine with that, once cosine agreed to refund me the money for those extra days. Well I moved out and cosine never refunded the money and they just ignored all of my emails. DECEITFUL COMPANY. DON'T USE THEM.
Michael C.
May 24, 2018
I rented a property from CoSine and everything was fine until it came time to check out. We managed to get our entire deposit back because we kept the house in great shape while we lived there, however, CoSine asked if we could move out 2 days early, on a Friday, so they could get another tenant moved in over the weekend. We agreed, with the understanding and explicit written email from Martha that we would be refunded those 2 days of rent, about $130. However, we didn't receive it with our security deposit and several emails to Jeremy went ignored. It's silly for them to get a bad review over $130. Especially considering they jacked the rent up an extra $200/month right when we moved out.
Sarah Crump
Nov 29, 2017
Do not waste your time dealing with this company! Completely unprofessional! Their agent, Jody, would not allow us to see an apartment because we couldn't find parking. We looked for 10 minutes and finally double parked and she turned us away. They did not provide a number for her and she did not try to reach us despite having our number. I'm just thankful we didn't get stuck with a year long commitment to this disreputable operation!
Chandra G.
Jun 21, 2017
Horrible. Don't waste your time! Do not answer calls. Schedule a showing and 5 minutes before they say it was canceled. They said it was our fault we did not call to verify the appointment even though the night before they confirmed. How is that our fault! They should've called us as soon as they knew. Instead we came from far away and then they blamed us. Ha! Pretty sure this is a fake property management company. Stay away.
Bob V.
May 09, 2017
Went to see a place advertised as a 3/1 in a neighborhood we used to live in. We had other things to do in the area, so got there about 20 min early. Agent was already there, but wasn't letting us in. Fine. We come back in 20 minutes to find she's queuing people like it's an amusement ride. Did I mention this was supposed to be an "open house".

Our name is called, and we go in to find a 2/1 with a very small third bedroom that's ruined the dining room spacing to the point where we can't figure out where the table would go. Ok, so they aren't responsible for owner mangling their property, but if they had advertised it as a 2/1 with bonus room, would have gotten more realistic expectations from prospective renters.

Fast forward to a few weeks later, we see some properties listed for pretty good price in areas we're looking to move to. I contact them through the site, nothing. Phone call and leave message, nothing. Doesn't matter if it's during business hours or not, NOTHING. Finally got a response today. How? craigslist anonymous email. Even though it was for another property, confirmed that is the best way to reach them. So FYI, for any other prospective renters that see something managed by Cosine. If you want to take the plunge, use any craigslist add by them to get a hold of someone.
Adam P.
Apr 27, 2017
Lady who showed us the apartment was perfectly nice and polite. As suggested we applied online and put down a nominal application fee. Heard nothing after leaving 3 separate voicemails. As other reviews mentioned: they do not answer their phones. If this is at all indicative of their management style before I've even rented from them I dread to think how they would deal with routine apartment maintenance. Unprofessional and they wasted my time. I will take my business elsewhere.
Ashley V.
May 04, 2016
When I moved in, there was no one doing walk through upon moving in. When I moved out, I requested the walk through and the lady did not even bring a checklist to confirm anything in writing. Upon my move out, I sent a 30 days notice and I specifically counted 30 days, they charge me for 32 days and explain that it "wasn't pro-rated." it makes no sense and unreasonable considering they don't tell the people that beforehand (super shady).

The person conducting the walk through even accuse me of taking the keys when I handed over all the keys on the day. As a person who always pay the rents and are always on time, they're are really reaping people's money very unnecessary. I would not recommend this apartment complex as they are very unprofessional when it comes to conducting business.

The apartment itself is nice on the inside, but the neighbors have pets and the dogs are always barking. The wall are thin so you practically hear people walking if you live on the first floor.
Michelle M.
Feb 13, 2016
After a difficult time with a need to move quickly under stressful circumstances, I found Mr Sine to be exceptionally professional and compassionate. The house we had rented was lovely and I was very sad to have to leave it. In the months that followed as we sorted through the mess, his approach was considerate and respectful. Our return of deposit in part was explained well and done fairly under the circumstances. I would not hesitate to request assistance from Cosine Realty with finding housing if I should need it in this part of California again.
Bruce B.
Dec 31, 2015
Owner beware: not the type of company you want to trust with your property. They are horrible at choosing renters.
Yoav L.
Sep 18, 2015
Second time I have been stood up to see the house. Can't believe people do business this way. Wanted to see a property for rent 427 smoky circle in Chula Vista. Very unprofessional representation.