[RE-wrenches] More Off-Grid Whole House RO

Fri May 9 14:15:43 PDT 2025

It's a tough location. Barrier island on the Gulf of Whatever you call it.
The highest point on the island is about 3 feet above sea level. I think
they are using the RO water for showers, laundry, etc. Drinking water is
all bottled. But they have 5 ice makers, so I'm not sure where that comes
from. Efficiency wasn't considered when it was built.

Jason Szumlanski
Principal Solar Designer | Florida Solar Design Group
NABCEP Certified Solar Professional (PVIP)
Florida State Certified Solar Contractor CVC56956
Florida Certified Electrical Contractor EC13013208

On Fri, May 9, 2025, 11:33 AM Dana Orzel via RE-wrenches <
re-wrenches at lists.re-wrenches.org> wrote:

> Suggestion :
>
> I start with a thorough water test: I have used these folks at National
> Testing Labs for 20+ years. Excellent service!
>
> @ (440) 449-2525        https://watercheck.com/
>
>
>
> Multipage test results for lots of different stuff in water talk with them
> about what you have and what test they would suggest.
>
>
>
> If you want, contact me off list glad to send a copy of my house well test
> for your perusal.
>
>
>
> With the data they provide you from can narrow down what it is that you
> are wanting to be rid of & this opens up the options for treatment &
> filtration.
>
>
>
> I filter for 2 specific items: very light arsenic [1 refillable cartridge
> for this] & sulfur dioxide [we have hot springs down 600’ below the surface
> & at high water times of the year slight sulfur smell turns out a carbon
> filter eliminates this]. 2 issues & 2 filters, done.
>
>
>
> I hope this helps & does not muddy the water, Ha!
>
>
>
> _________________________________________________________
>
> Dana Orzel                GREAT SOLAR WORKS!
>
> C – 208.721.7003      E – dana at solarwork.com
>
> W - www. greatsolarworks.com     www.solarwork.com
>
> *“Responsible Technologies for Responsible People since 1988!”*
>
>
>
>
>
> ---------- Forwarded message ----------
> From: Dana Orzel via RE-wrenches <re-wrenches at lists.re-wrenches.org>
> To: RE-wrenches <re-wrenches at lists.re-wrenches.org>
> Cc: Dana Orzel <dana at solarwork.com>
> Bcc:
> Date: Fri, 9 May 2025 18:10:24 +0000
> Subject: [RE-wrenches] Off-Grid Whole House RO
>
> I really have not been following this but: IMHO RO off grid is wasteful &
> not appropriate.
>
>
>
>    1. There are RO systems that use a lot less water than other RO
>    systems. All RO systems are not equal.
>    2. There are many filtration systems that can do what RO does without
>    wasting any water at all. You will go thru filters though.
>    3. I understand the brackish/salt? Issue I have done large house sized
>    RO systems to a 2,500-gallon tank in CO.
>    4. The challenge with most water filtration companies is they are used
>    to the grid - lots of power & unlimited waste.
>    5. Haul or get delivered water? Had a few folks back in the day with
>    solid rock under there place with no water under the rock.
>    6. **. Assuming the RO system doesn’t need rhe 1.25hp pump ( i  am
>    assuming the RO goes into a tank and much then has a pressure pump to
>    supply the house. If it doesn’t I would recommend installing said design)
>    I’d install a smaller motor and pump head to better match the RO flow rate.
>    You could look at getting a high efficiency DC pump or 3 phase with
>    vfd.
>    Sun pumps has such things.
>    7. I like #6 so far…
>    8. Maybe Ro at a few locations for drinking & a lesser filtrated water
>    for shower etc?
>
>
>
>
> _________________________________________________________
>
> Dana Orzel                GREAT SOLAR WORKS!
>
> C – 208.721.7003      E – dana at solarwork.com
>
> W - www. greatsolarworks.com     www.solarwork.com
>
> *“Responsible Technologies for Responsible People since 1988!”*
>
>
>
>
>
> ---------- Forwarded message ----------
> From: Jason Szumlanski via RE-wrenches <re-wrenches at lists.re-wrenches.org>
> To: RE-wrenches <re-wrenches at lists.re-wrenches.org>
> Cc: Jason Szumlanski <jason at floridasolardesigngroup.com>
> Bcc:
> Date: Fri, 9 May 2025 17:53:55 +0000
> Subject: Re: [RE-wrenches] Off-Grid Whole House RO
> That is what I was thinking, that the RO booster pump doesn't need a lot
> of pressure on the inlet side. There is a lot of wastewater, but I have not
> calculated the ratio. My visual analysis is that is it more like 6:1 or
> more. The production level is very low, perhaps 1-2 gallons per minute. I
> would love to not have a well pump running at all when producing RO,
> pumping raw water into a holding tank in advance of RO production. I don't
> think the owner is opposed to managing this manually, but it could also be
> set up on a solar direct DC pump or on a smart load output of the inverters
> if using an AC pump.
>
> The house does have rainwater catchment that is great in the summer,
> producing 100% of its needs. However, the property is more heavily used in
> the dry winter months. So the rainwater system doesn't align with the use
> case for the home (vacation/second home in the nice season in Florida).
>
> Jason Szumlanski
> Principal Solar Designer | Florida Solar Design Group
> NABCEP Certified Solar Professional (PVIP)
> Florida State Certified Solar Contractor CVC56956
> Florida Certified Electrical Contractor EC13013208
>
>
> On Thu, May 8, 2025 at 3:22 PM Jay via RE-wrenches <
> re-wrenches at lists.re-wrenches.org> wrote:
>
>> Hi Jason
>>
>> What’s the actual water output from
>> The RO? We had one at our house before I took it out and replaced the
>> house water with rainwater catchment. 3 yrs and counting in the high
>> desert.
>> I couldn’t live with the 2-3 to 1 loss ratio.
>>
>> A few options as I suspect the actual RO output is closer to 1-2 gpm.
>> 1. Use a 1/3hp well pump into a large pressure tank with relatively low
>> pressure switch.  You might even get away with a small sump pump. The RO
>> should t need but minimal input pressure
>>
>> 2. Assuming the RO system doesn’t need rhe 1.25hp pump ( i  am assuming
>> the RO goes into a tank and much then has a pressure pump to supply the
>> house. If it doesn’t I would recommend installing said design) I’d install
>> a smaller motor and pump head to better match the RO flow rate.
>> You could look at getting a high efficiency DC pump or 3 phase with vfd.
>> Sun pumps has such things.
>>
>> Jay
>>
>>
>>
>> > On May 8, 2025, at 12:38 PM, Jason Szumlanski via RE-wrenches <
>> re-wrenches at lists.re-wrenches.org> wrote:
>> >
>> > 
>> > Water pump is not my strong suit. I usually leave that up to the
>> experts around here. Unfortunately, the experts are clueless when it comes
>> to off-grid living. I have a client with a setup that is pretty unworkable.
>> I'm trying to give him some general guidance.
>> >
>> > The setup uses a brackish water (might as well be salt water) very
>> shallow well. It is about 3 ft underground for the water table. The RO
>> system installer has a 1 HP 1.25 SF Century centrifugal surface pump
>> drawing water from the well and pressurizing the inlet of a StaRite 1.25 HP
>> booster pump designed for about 10 GPM at 150 PSI to run water through the
>> RO system.
>> >
>> > Both of the pumps run simultaneously and continuously when producing
>> water, and the water production is ridiculously low. I understand that RO
>> production is going to be slow, but the amount of power these pumps are
>> using is pure insanity. I have advised the client that, at a minimum, this
>> system needs to be on a smart load circuit to run only when there is
>> adequate battery capacity. The startup surgery is not a concern, but it
>> does flicker the lights and it makes quite the racket.
>> >
>> > My thoughts are that the well pump is drastically oversized. The
>> booster pump only needs 10 gallons per minute, and it has a suction head of
>> 15 ft. I don't even know if the well pump pressurizing the booster pump
>> inlet is required. I'm thinking we should be slow pumping water into an
>> interim holding tank at least at the height of the booster pump. At a
>> minimum, the well pump should be on a pressure switch with pressure tank so
>> it can cycle.
>> >
>> > Can anyone give me some general guidance, and perhaps a VFD pump that
>> does not have the startup surge and is maybe more efficient? During times
>> of heavy use, the RO system can easily eat up half of the PV produced
>> during a day at this site.
>> >
>> >
>> > Jason Szumlanski
>> > Florida Solar Design Group
>> > _______________________________________________
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