אורח חיים מ״גOrach Chayim 43

Se’if 1א׳

אָסוּר לִכָּנֵס לְבֵית הַכִּסֵא קָבוּעַ לְהַשְׁתִּין בִּתְפִלִּין שֶׁבְּרֹאשׁוֹ, גְּזֵרָה שֶׁמָּא יַעֲשֶׂה בָּהֶם צְרָכָיו, וְאִם אוֹחֲזָן בְּיָדוֹ, מֻתָּר לְהַשְׁתִּין בָּהֶם בְּבֵית הַכִּסֵא קָבוּעַ: הַגָּה: וְהַיְנוּ דַּוְקָא כְּשֶׁמַּשְׁתִּין מְיֻשָּׁב דְּלֵיכָּא לְמֵיחַשׁ לְנִצּוֹצוֹת, אֲבָל מַשְׁתִּין מְעֻמָּד פְּשִׁיטָא דְּאָסוּר, דְּלֹא עָדִיף מִבֵּית הַכִּסֵּא עֲרַאי, וְה"ה אִם מַשְׁתִּין מְיֻשָּׁב אוֹ בְּעָפָר תָּחוּחַ דְּלֵיכָּא נִצּוֹצוֹת, בְּבֵית הַכִּסֵּא עֲרַאי נָמֵי שָׁרֵי, וְאֵין חִלּוּק בֵּין קֶבַע לְעֲרַאי לְעִנְיָן זֶה, אֶלָּא דְּבֵית הַכִּסֵּא קָבוּעַ מִסְּתָמָא עוֹשֶׂה צְרָכָיו מְיֻשָּׁב, וּבֵית הַכְּנֶסֶת עֲרַאי מִסְּתָמָא עוֹשֶׂה מְעֻמָּד, הוֹאִיל וְאֵינוֹ נִפְנֶה לִגְדוֹלִים (בֵּית יוֹסֵף בְּשֵׁם נ"י וּמִגְדּוֹל עֹז): וּבְבֵית הַכִּסֵא עֲרַאי מֻתָּר לְהַשְׁתִּין בָּהֶם כְּשֶׁהֵם בְּרֹאשׁוֹ, אֲבָל אִם אוֹחֲזָן בְּיָדוֹ אָסוּר לְהַשְׁתִּין בָּהֶם מְעֻמָּד, אֲפִלּוּ אִם תּוֹפֵס אוֹתָם בְּבִגְדּוֹ, מִפְּנֵי שֶׁצָּרִיךְ לְשַׁפְשֵׁף בְּיָדוֹ נִיצוֹצוֹת שֶׁבְּרַגְלָיו, אֶלָּא חוֹלְצָן בְּרִחוּק ד' אַמּוֹת וְנוֹתְנָם לַחֲבֵרוֹ. וּמִדִּבְרֵי הַרַמְבַּ"ם נִרְאֶה שֶׁאָסוּר לְהַשְׁתִּין כְּשֶׁהֵם בְּרֹאשׁוֹ, בֵּין בְּבֵית הַכִּסֵא קָבוּעַ בֵּין בְּבֵית הַכִּסֵא עֲרַאי, וְיֵשׁ לָחוּשׁ לִדְבָרָיו.

Laws regarding how to conduct oneself with תפילין upon entering the bathroom. And there are 9 Se'ifim: It is forbidden to enter a permanent bathroom to urinate with his head תפילין on out of concern that he may come to defecate. [But] if holds them in his hand, it is permitted to urinate with them in a permanent bathroom. Rema: And this is specifically if he is urinating while sitting, for then there is no concern for [urine] droplets [splashing on him]. But urinating while standing is obviously forbidden, for it is no better than a temporary bathroom. And the same law applies if he urinates while sitting or into soft dirt which [ produces] no [splashing] droplets... [and this is referring to when done] in a temporary bathroom which is also permitted. And there is no difference between a permanent and temporary [bathroom] regarding [all] this except that in a permanent bathroom one generally urinates while sitting, and in a temporary bathroom one urinates while standing since he doesn't intend to defecate (Beit Yosef in the name of Nimukei Yosef and Migdol Oz). And in a temporary bathroom it is permitted to urinate with them (ie. his head תפילין) on his head, but if he's holding them in his hand it is forbidden to urinate while standing... even if he's holding them [while wrapped] in his clothing since he'll need to use his hands to wipe the droplets that are on his legs. Rather, he should remove them (ie. his head תפילין) [while at] a distance of 4 cubits [from the bathroom] and give them to his friend [to hold for him]. And from the words of the Ramba"m it seems that it's forbidden to urinate when they are on his head... whether it's a permanent bathroom or a temporary bathroom... and one should be concerned for his words.

Se’if 2ב׳

בֵּית הַכִּסֵא קָבוּעַ הַיְנוּ שֶׁיֵּשׁ בּוֹ צוֹאָה, וְהוּא עַל פְּנֵי הַשָּׂדֶה בְּלֹא חֲפִירָה.

A permanent bathroom is one where there is excrement [there] and it is on the ground/field without being in a ditch.

Se’if 3ג׳

בֵּית הַכִּסֵא עֲרַאי, הַיְנוּ כְּגוֹן לְהַשְׁתִּין מַיִם שֶׁאֵין אָדָם הוֹלֵךְ בִּשְׁבִילָם לְבֵית הַכִּסֵא, וְהַפַּעַם הַזֹּאת נַעֲשָׂה הַמָּקוֹם הַזֶּה בֵּית הַכִּסֵא תְּחִלָּה.

A temporary bathroom is one where [one goes], for example, to urinate [which is something that] a person does not need a bathroom [with a seat] for. And [his urinating] this time is making this place into a bathroom for the first time.